
Introduction
It's been a busy time for Dell recently, with all
kinds of new models being released in their ever-popular monitor range. We
have reviewed their new UltraSharp 24" class models, the
U2414H and
U2415, and recently their new 27"
U2715H. We've got something a bit different from Dell with us now, their new
25" sized U2515H screen. This is the first 25" display we've reviewed and is
something other manufacturers are also looking at with their upcoming line-ups.
The U2515H offers the same 2560 x 1440 resolution as the wide range of 27"
screens on the market today, but on a smaller screen to give you a higher DPI
(dots per inch), and importantly also at a much lower retail cost. The U2515H has
al almost identical appearance, spec and feature set to the U2414H (23.8" in
size) and U2715H (27"), but in an intermediate screen size. It offers a modern
IPS panel and all the features and extras we've come to know from Dell's
UltraSharp range. We are keen to see if it can offer the same high quality
performance as the other sized models.
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Dell U2515H Now Available

Specifications and Features
The following table gives detailed information
about the specs of the screen:
Monitor
Specifications |
Size |
25"WS (63.44 cm) |
Panel Coating |
Light AG coating |
Aspect Ratio |
16:9 |
Interfaces |
1 DisplayPort
(version 1.2)
|
Resolution |
2560 x 1440 |
Pixel Pitch |
0.216 mm |
Design
colour |
Matte black bezel with silver stand/base |
Response Time |
6ms G2G (Fast mode)
8ms G2G (normal mode) |
Ergonomics |
Tilt, height, swivel and rotate |
Static Contrast Ratio |
1000:1 |
Dynamic Contrast Ratio |
2 million:1 |
VESA Compatible |
Yes 100mm |
Brightness |
50 - 350 cd/m2 |
Accessories |
Cable cover, power, DisplayPort to Mini DP
cable, USB cable, factory calibration report |
Viewing Angles |
178 / 178 |
Panel Technology |
LG.Display AH-IPS |
Weight |
monitor without stand: 4.4Kg |
Backlight Technology |
W-LED |
Physical Dimensions |
(WxHxD with stand height range)
569.0 x 398.0 - 512.5 x 205.0 mm |
Colour Depth |
16.78m (8-bit) |
Refresh Rate |
60Hz |
Special
Features |
5x
USB 3.0 ports (1 fast charge), DisplayPort out, audio out, factory
calibration |
Colour Gamut |
Standard gamut
99%
sRGB, ~72% NTSC |
The U2515H offers a good range of modern
connectivity options which are identical to the recent U2414H/U2415/U2715H
screens as well. There are 2x HDMI (with MHL), 1x DisplayPort and 1x Mini
DisplayPort input interfaces provided for video connections. There is also a
DisplayPort out connection for daisy chaining several screens. There is no DVI
or D-sub offered here which might be a bit of a pain for older systems and
graphics cards. Cables are provided in the box for only DP > Mini DP. We
understand from a few reports that you can actually use a DVI to HDMI adapter to
output from a DVI graphics card, to HDMI input on the monitor. This might
require a dual-link DVI > HDMI converter given the resolution (to be safe at
least) and you may need to create a custom resolution from your graphics card as
it seems the 2560 x 1440 @ 60Hz is not automatically detected. It does seem to
work though, providing compatibility with DVI graphics cards at least. DVI to
DisplayPort is more tricky and would require an active adapter which can be
quite expensive and may be more hit and miss.
The screen has an internal power supply so there
is only the need for a kettle lead power cable (provided). There are several additional
features as well for this screen. These include a factory calibration, 5x USB 3.0 ports
(1 with battery charging support) and an audio out port. The screen is
compatible with Dell's SoundBar as well if you want (sold separately).
Below is a summary of the features and connections
of the screen:
Feature |
Yes / No |
Feature |
Yes / No |
Tilt adjust |
 |
DVI |
 |
Height adjust |
 |
HDMI |
 |
Swivel adjust |
 |
D-sub |
 |
Rotate adjust |
 |
DisplayPort |
 |
VESA compliant |
 |
Component |
 |
USB 2.0 Ports |
 |
Composite |
 |
USB 3.0 Ports |
 |
Audio connection |
 |
Card Reader |
 |
HDCP Support |
 |
Ambient Light Sensor |
 |
MHL Support |
 |
Human Motion Sensor |
 |
Integrated Speakers |
 |
Touch Screen |
 |
PiP / PbP |
 |
Factory Calibration |
 |
Blur Reduction Mode |
 |
Hardware calibration |
 |
G-Sync |
 |
Uniformity correction |
 |
FreeSync |
 |

Design and Ergonomics

Above: front view of the screen. Click for larger version
The U2515H comes in a black and silver
design. The front bezel of the screen is a matte black plastic and
provides a very thin outer edge to the screen. The actual plastic measures
~1mm along the sides and top, and the bottom bezel is a modest 15mm as
well. Before people get too excited about the 1mm outer bezel, there is
also a ~6.9mm wide border to the panel before the actual image
starts. All in all, it's still only a 7.9mm edge around the image which
looks very nice in practice and should be very good for multi-screen
setups.
There is a shiny silver Dell logo in the
middle of the bottom bezel, but no other writing or model designations at
all. In the bottom right hand corner are the four touch-sensitive OSD
control buttons and also a touch-sensitive power on/off button. There is a
small LED light underneath the power button which glows white during
normal operation and pulsates on/off white when the screen is on standby. Unlike some of the other UltraSharp screens we've seen
the OSD control buttons don't light up at all on the front of the bezel to
identify themselves, so you have to actually press the small grey circle
to operate the control.

Above: view
of the stand and base. Click for larger version
The stand is different to the mostly black
style stands of some older UltraSharp models, and comes in an all-silver colour.
Matte plastics are again used for the stand and base. The base measures
~245 (width) x 205 mm (depth) and provides a sturdy support for the
screen. From the side the screen offers a pretty
thin profile thanks to the use of W-LED backlighting. The
stand is silver in design along the edges and back as well.

Above: rear view of the screen. Click for larger version

Above:
cable tidy in back of the stand
The back of the screen is finished in a
matte black plastic and is rounded off to look smooth and sleek. There is
a useful cable tidy hole in the back of the stand. There is even a
detachable black plastic section at the bottom of the back of the screen
which can hide the cabling connections. You will
notice the single USB 3.0 port on the back as well (right hand side in
top of the two above images) which also has charging capabilities. Useful to have one
easier access port offered here.

The screen provides a full range of
ergonomic adjustments from the stand which is good to see. It can also be
easily detached so you can wall or arm-mount the screen (VESA 100mm).


Above: full
range of tilt adjustment shown. Click for larger versions
The tilt function is smooth but a little
stiff to move, but it does offer a wide range of angles to choose.

Above: full
range of height adjustment shown. Click for larger versions
Height adjustment is a little easier to move and is
smooth, offering a very good range of
adjustment again. At the lowest height setting the bottom edge of the
screen is approximately 60mm from the edge of the desk. At the maximum
setting it is ~170mm, and so there is a 110 mm total adjustment range
available here.
Side to side swivel is has a smooth movement
which is again easy to operate and it swivels properly as it should
without the base moving.

The rotate function is a stiff but smooth
enough to move if you want to switch into portrait mode. Overall when making
adjustments to your viewing angle and position the screen remains stable on
the desk and there is minimal wobble from the screen.
A summary of the screens ergonomic adjustments
is shown below:
Function |
Range |
Smoothness |
Ease of Use |
Tilt |
Yes |
Smooth |
A little stiff |
Height |
110mm |
Smooth |
Easy |
Swivel |
Yes |
Smooth |
Easy |
Rotate |
Yes |
Quite Smooth |
Stiff |
Overall |
Good range of adjustments and
easy enough to use overall. |
The materials were of a good standard and the
build quality felt good as well. There was no audible noise from the screen,
even when conducting specific tests which can often identify buzzing issues.
The whole screen remained very cool even during prolonged use as well which
was pleasing.

Above: rear
views of the screen showing connections.
The back of the screen provides connections for
the power cable which is provided with the screen. There are then
video connections for 2x HDMI, DisplayPort, Mini DisplayPort, DisplayPort out (for
daisy chaining), audio output, USB upstream and 4x USB 3.0
downstream. One USB connection is separated from the other three on the far
right hand side.

Above: view of
rear USB 3.0 connection on back of screen. Click for larger version
An additional easier access USB port is also
available a little above these connections in the back of the screen. It might
have been better to include this on the side of the screen perhaps for easier
access although the profile of the screen is very thin so this might not have
been possible. This port supports charging of devices.

OSD Menu

Above: OSD control buttons on the bottom right hand edge
The OSD menu is accessed and controlled through a
series of 5 touch-sensitive buttons located on the bottom right hand edge of the
bezel. There are small grey circles on the bezel marking where the buttons are
which are discrete. They don't light up at all, even when pressed. There is a
small power LED bar underneath the power button which glows white during use and
pulsates white on/off when the screen is on standby. We did find that sometimes
the buttons were a little unresponsive when you first press them, but seemed to
work better once you were within the menu sections.

Pressing any of the buttons pops up the quick
access menu which is shown above. From here by default you have quick access to
the preset modes from button 1, input selection (actually shown as
brightness/control above) from button 2, the main menu (3) and a button to exit
(4). The power on/off button is shown as well, as button 5 above. You can
personalize the quick access options here through the main OSD if you want.
The menu is basically identical to the U2415 so we
will keep most of the same screenshots we used in that review to save some time.
Obviously the model name shows as Dell U2515H at the top, and the resolution
notification at the bottom shows as 2560 x 1440 at 60Hz. The rest is largely
unchanged, except for the aspect ratio options which we talk about below.

Using the quick access options pops up a smaller
menu above specific to that selection. For instance the input selection quick
access menu is shown above.

The main menu is split in to 8 sections shown down
the left hand side of the screen. The options available in each section are then
displayed on the right hand side. The first section is the brightness and
contrast menu which is self explanatory.

The second section allows you to change the input
being used.

The 'color' menu gives you access to a few
options, mainly useful for accessing the preset mode menu. you can also enter
into the 'custom color' mode which then allows you to manually alter the RGB
channels for
calibration.

The preset mode menu is shown above and you can
see the 7 options available.

The 'Display' menu has a few useful extra
features. This includes the aspect ratio control menu (options for 16:9 wide,
4:3 and 5:4). You can also change the
response time
setting here. We have updated the screenshot here to be specifically from
the U2515H since the aspect ratio options are different here than on the U2415
(which had 16:10 aspect ratio option instead of 16:9).

The 'energy' section allows you to control the
power LED and USB ports.



The other sections are self-explanatory really
from the pictures above.
All in all the menu was very easy to navigate and
well laid out. The control buttons were mostly responsive and sensitive, and the
touch-sensitive nature gave them a premium feel. Sometimes when you first try to
bring up the menu they required a few presses to get going. There were quite a few options
to play around with as well, and the ability to customise the quick access menu
was useful. The menu also remembered which section you were last in when you
exit which is quite handy.

Power Consumption
In terms of power consumption the manufacturer
lists typical usage of 35.0W and less than 0.5W in standby. They also list
maximum power usage of 87.0W (*) but this is with maximum brightness, Dell
SoundBar and USB connected also. We carried out our normal tests to
establish its power consumption ourselves.
 |
State and Brightness
Setting |
Manufacturer Spec (W) |
Measured Power Usage
(W) |
Default (50%) |
35.0 |
26.3 |
Calibrated (20%) |
- |
19.2 |
Maximum Brightness (100%) |
87.0 * |
38.4 |
Minimum Brightness (0%) |
- |
14.6 |
Standby |
<0.5 |
0.6 |
|
We tested this ourselves and found that out of the
box the screen used 26.3W at the default 50% brightness setting. Once calibrated the screen reached
19.2W consumption, and in standby it
used only 0.6W. We have plotted these results below compared with other screens
we have tested. The consumption is comparable actually to the other W-LED
backlit displays we have tested, with GB-r-LED backlit displays (Dell U2713H,
ViewSonic VP2772) using a bit more than most W-LED backlights.


Panel and Backlighting
Panel Manufacturer |
LG.Display |
Colour Palette |
16.78 million |
Panel Technology |
AH-IPS |
Colour Depth |
8-bit |
Panel Module |
LM250WQ1-SSA1 |
Colour space |
Standard gamut |
Backlighting Type |
W-LED |
Colour space coverage (%) |
99% sRGB, ~72% NTSC |
Panel Part and Colour Depth
The Dell U2515H features an
LG.Display LM250WQ1-SSA1 AH-IPS panel which is capable of producing 16.78 million colours.
This is LG.Display's new "Neoblade" panel, featuring a borderless design
allowing for the ultra-thin bezel. The panel offers an 8-bit colour depth and
the part is confirmed when
dismantling the screen:


Screen
Coating
The
screen coating on the U2515H is a light anti-glare (AG) offering. It isn't a
semi-glossy coating, but it is light as seen on other modern IPS type panels
including other recent screens like the U2715H and U2415 for instance. Thankfully it
isn't a heavily grainy coating like some old IPS panels feature, including the
older U2711 model. It retains its anti-glare properties to avoid too many
unwanted reflections of a full glossy coating, but does not produce an too
grainy or dirty an image that some thicker AG coatings can. There were some
very slight cross-hatching patterns visible on the coating if you looked very
closely, but nothing to the extent of what some people find problematic on the
U2713HM model.
Backlight Type and Colour Gamut
The screen uses a White-LED (W-LED) backlight unit
which has become very popular in today's market. This helps reduce power
consumption compared with older CCFL backlight units and brings about some
environmental benefits as well. The W-LED unit offers a standard colour gamut
which is approximately equal to the sRGB colour space (99% sRGB quoted).
Anyone wanting to work with wider colour spaces would need to consider wide
gamut CCFL screens or the newer range of GB-r-LED type displays available
now. If
you want to read more about colour spaces and gamut then please have a read of
our
detailed article. Dell have wide gamut models available in 24" 1920 x 1200
(U2413), 27" 2560 x 1440 (U2713H) and larger models if you need wide gamut support.
Backlight
Dimming and Flicker
We tested the screen to establish the methods used
to control backlight dimming. Our in depth article talks in more details about a
common method used for this which is called
Pulse Width Modulation (PWM). This in itself gives cause for concern to some
users who have experienced eye strain, headaches and other symptoms as a result
of the flickering backlight caused by this technology. We use a photosensor +
oscilloscope system to measure backlight dimming control
with a high level of accuracy and ease. These tests allow us to establish
1) Whether PWM is being used to control the
backlight
2) The frequency and other characteristics at which this operates, if it is used
3) Whether a flicker may be introduced or potentially noticeable at certain
settings
If PWM is used for backlight dimming, the higher
the frequency, the less likely you are to see artefacts and flicker. The duty
cycle (the time for which the backlight is on) is also important and the shorter
the duty cycle, the more potential there is that you may see flicker. The other
factor which can influence flicker is the amplitude of the PWM, measuring the
difference in brightness output between the 'on' and 'off' states. Please
remember that not every user would notice a flicker from a backlight using PWM,
but it is something to be wary of. It is also a hard thing to quantify as it is
very subjective when talking about whether a user may or may not experience the
side effects.
100% 50%
0%

Above scale = 1
horizontal grid = 5ms
At 100% brightness a constant voltage is applied
to the backlight. As you reduce the brightness setting to dim the backlight a
Direct Current (DC) method is used, as opposed to any form of PWM. This applies
to all brightness settings from 100% down to 0%. The screen is flicker free as a
result.
Pulse Width
Modulation Used |
No |
Cycling
Frequency |
n/a |
Possible
Flicker at |
|
100% Brightness |
No |
50% Brightness |
No |
0% Brightness |
No |
For an up to date list of all flicker-free (PWM free) monitors please see our
Flicker Free Monitor Database.

Contrast
Stability and Brightness
We wanted to see how much variance there was in
the screens contrast as we adjusted the monitor setting for brightness.
In theory, brightness and contrast are two independent parameters, and good
contrast is a requirement regardless of the brightness adjustment.
Unfortunately, such is not always the case in practice. We recorded the
screens luminance and black depth at various OSD brightness settings, and
calculated the contrast ratio from there. Graphics card settings were left at
default with no ICC profile or calibration active. Tests were made using an
X-rite i1 Display Pro colorimeter. It should be noted that we used the
BasICColor calibration software here to record these, and so luminance at
default settings may vary a little from the LaCie Blue Eye Pro report.
OSD
Brightness |
Luminance
(cd/m2) |
Black
Point (cd/m2) |
Contrast
Ratio
( x:1) |
100 |
383.45 |
0.38 |
1009 |
90 |
351.25 |
0.32 |
1098 |
80 |
321.69 |
0.29 |
1109 |
70 |
290.80 |
0.26 |
1118 |
60 |
261.03 |
0.24 |
1088 |
50 |
230.83 |
0.21 |
1099 |
40 |
192.69 |
0.18 |
1070 |
30 |
153.69 |
0.14 |
1098 |
20 |
115.48 |
0.11 |
1050 |
10 |
74.80 |
0.07 |
1069 |
0 |
35.04 |
0.03 |
1168 |
Total Luminance Adjustment Range
(cd/m2) |
348.41 |
Brightness OSD setting controls backlight? |
 |
Total Black Point
Adjustment Range (cd/m2) |
0.35 |
Average Static Contrast Ratio |
1089:1 |
PWM Free? |
 |
Recommended OSD setting
for 120 cd/m2 |
21 |
The brightness control gave us a very good range
of adjustment. At the top end the maximum luminance reached 383.45
cd/m2 which was
high, and even a fair bit higher than the specified maximum brightness of 350 cd/m2
from the manufacturer. There was a decent 348.41 cd/m2 adjustment
range in total, and so at the minimum setting you could reach down to a low
luminance of 35.04 cd/m2, lower than the specified 50 cd/m2
from the manufacturer as well. This should be more than adequate for those
wanting to work in darkened room conditions with low ambient light. A setting of
21 in the OSD menu should return you a
luminance of around 120 cd/m2 at default settings.
It should be noted that the
brightness regulation is controlled without the need for
Pulse Width Modulation, using a Direct Current (DC) method for all brightness settings
between 100 and 0% and so the screen is flicker free.

We have plotted the
luminance trend on the graph above. The screen behaves as it should in this
regard, with a reduction in the luminance output of the screen controlled by the
reduction in the OSD brightness setting. This is not quite a linear relationship as
the brightness adjustments between settings of 50 and 0 controls a slightly steeper
luminance range than settings between 100 and 50.

The average contrast ratio of
the screen was excellent for an IPS panel with an average of 1089:1. This was
pretty stable across the brightness adjustment range as shown above although at
the top and bottom end of the brightness range it did fluctuate a little.

Testing
Methodology
An
important thing to consider for most users is how a screen will perform out of
the box and with some basic manual adjustments. Since most users won't have
access to hardware colorimeter tools, it is important to understand how the
screen is going to perform in terms of colour accuracy for the average user.
We restored our graphics card to default settings and disabled any previously active
ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using
an
X-rite i1
Pro Spectrophotometer (not to be confused with the i1 Display Pro
colorimeter) combined with
LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro colorimeter was
also used to verify the black point and contrast ratio since the i1 Pro
spectrophotometer is less
reliable at the darker end.
Targets for these tests are as follows:
-
CIE Diagram - validates the colour space
covered by the monitors backlighting in a 2D view, with the black triangle representing the
displays gamut, and other reference colour spaces shown for comparison
-
Gamma - we aim for 2.2 which is the default
for computer monitors
-
Colour temperature / white point - we aim
for 6500k which is the temperature of daylight
-
Luminance - we aim for 120
cd/m2, which is
the recommended luminance for LCD monitors in normal lighting conditions
-
Black depth - we aim
for as low as possible to maximise shadow detail and to offer us the best
contrast ratio
-
Contrast ratio - we aim
for as high as possible. Any dynamic contrast ratio controls are turned off here
if present
-
dE average / maximum -
as low as possible.
If DeltaE >3, the color displayed is significantly different from the
theoretical one, meaning that the difference will be perceptible to the
viewer.
If DeltaE <2, LaCie considers the calibration a success; there remains a
slight difference, but it is barely undetectable.
If DeltaE < 1, the color fidelity is excellent.

Default Performance and
Setup
The Dell U2515H comes factory calibrated, showing
their focus on providing a high quality product suitable for colour critical
work. Like other recent UltraSharp models the screen is packaged with a calibration report
unique to your unit, confirming the targets set and met during that process.
Here they have factory calibrated the default 'Standard' preset mode to a 2.2 gamma, 6500k white point and with a
dE colour accuracy of <3. A copy of the calibration report from our unit is provided below for reference:

Default settings of the screen were as follows:
Monitor OSD Option |
Default Settings |
Brightness |
50 |
Contrast |
50 |
Preset mode |
Standard |
RGB |
n/a |

Dell U2515H - Default Settings / Factory Calibration



|
Default Settings |
luminance (cd/m2) |
248 |
Black Point (cd/m2) |
0.23 |
Contrast Ratio |
1096:1 |
Initially out of the box the screen was set in the
default 'standard' preset mode which carries the factory calibration discussed
above. The screen was bright as it was set at
a default 50% brightness setting. Colour balance and temperature felt
good, and you could tell it was a standard gamut screen. We went ahead and measured the default state with
the i1 Pro.
The
CIE diagram on the left of the image confirms that the monitors colour gamut
(black triangle) is roughly equal to
the sRGB colour space. There is some minor under-coverage in some green and red
shades but not by anything significant.
Default gamma was recorded at 2.2 average, leaving it with a very minor 1% deviance
from the target which was pleasing. White point was measured at 6626k
being close to the target of 6500k which was very good and with only a 2%
deviance.

Luminance was recorded at a bright 248
cd/m2 which is
too high for prolonged general use. The screen was set at a default 50%
brightness in the OSD menu but that is easy to change of course to reach a more
comfortable setting without impacting any other aspect of the setup. The black depth was 0.23 cd/m2 at this default
brightness setting, giving us an excellent (for a IPS panel) static contrast ratio of
1096:1.
Colour accuracy was pretty good out of the box
with a default dE average of 2.8, although a maximum of 6.3 showed there were
some errors. Testing the screen with various gradients showed smooth transitions
with no sign of any banding thankfully. There was some slight gradation evident
as you will see from most monitors in darker tones. Overall the default setup
was good, with the gamma and white point being decent. Looks like the
factory calibration does provide a reliable setup for the screen which should be
fine for most casual users once they've adjusted the brightness setting.
We also switched to the 'custom color' mode to
test that preset out of the box:
Monitor OSD Option |
Default Settings |
Brightness |
50 |
Contrast |
50 |
Preset mode |
Custom Color |
RGB |
100, 100, 100 |

Dell U2515H - Default Settings, Custom Color Preset

|
Default Settings,
Custom Color preset |
luminance (cd/m2) |
269 |
Black Point (cd/m2) |
0.23 |
Contrast Ratio |
1188:1 |
The Custom Color mode was not as reliable and
showed a significant difference in the gamma curve. Dark shades had a gamma much
lower than the desired 2.2, dropping down to 1.85 and resulting in an average
gamma overall of 1.9 (15% deviance from the target). White point was accurate, with a 0%
deviance. Colour accuracy had deteriorated a little, with dE average now of only
4.0 being measured. This mode is useful for calibration since you now have
access to the RGB channels, but you will need a calibration device to correct
the gamma curve. If you don't have one, you would probably be better sticking
with the default 'standard' mode and turning the brightness down to a
comfortable level. The 'custom color' default mode had a higher
contrast ratio (1188:1 here), since by default the RGB channels were all at 100.


Calibration
We used the
X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro
software package to achieve these results and reports. An X-rite i1 Display Pro
colorimeter was used to validate the black depth and contrast
ratios due to lower end limitations of the i1 Pro device.
Monitor OSD Option |
Calibrated Settings |
Brightness |
20 |
Contrast |
50 |
Preset Mode |
Custom Color |
RGB |
100, 93, 99 |

Dell U2515H - Calibrated Settings
|
Calibrated Settings |
luminance (cd/m2) |
122 |
Black Point (cd/m2) |
0.11 |
Contrast Ratio |
1138:1 |
We changed to the 'custom color' preset mode first
of all which would give us access
to the RGB channels, as well as the brightness and contrast settings which are
available in all the modes. All these OSD
changes allowed us to obtain an
optimum hardware starting point and setup before software level changes would be
made at the graphics card level. We left the LaCie software to calibrate
to "max" brightness which would just retain the luminance of whatever brightness
we'd set the screen to, and would not in any way try and alter the luminance at
the graphics card level, which can reduce contrast ratio. These adjustments
before profiling the screen would help preserve tonal values and limit
banding issues. After this we let the software carry out the LUT adjustments and create an
ICC profile.

Average gamma was now corrected to 2.2 average,
correcting the large 15% deviance we'd seen out of the box in this 'custom color' preset
mode. If you're using the 'custom color' mode, you need a calibration tool to
correct the gamma curve, which has an average of 1.9 out of the box. The
white point was maintained at an accurate level, measured at 6476k (0%
deviance). Luminance had been improved thanks to the adjustment to the brightness
control and was now being measured at 122
cd/m2. This
left us a black depth of 0.11 cd/m2 and maintained an excellent static contrast ratio
(for an IPS panel) of
1138:1. Colour accuracy of the resulting
profile was very good, with dE average of 0.4 and maximum of 0.9. LaCie would
consider colour fidelity to be very good overall.
Testing the screen with various colour gradients
showed mostly smooth transitions. There was some slight gradation in darker tones
but no banding introduced due to the adjustments to the
graphics card LUT from the profilation of the screen which was pleasing.
You can use our settings and
try our calibrated ICC profile if you wish, which are available in
our ICC profile database. Keep in mind that results will vary from one
screen to another and from one computer / graphics card to another.

Calibration Performance Comparisons

The comparisons made in this section try to give
you a better view of how each screen performs, particularly out of the box which
is what is going to matter to most consumers. When comparing the default factory
settings for each monitor it is important to take into account several
measurement areas - gamma, white point and colour accuracy. There's no point
having a low dE colour accuracy figure if the gamma curve is way off for
instance. A good factory calibration requires all 3 to be well set up. We have
deliberately not included luminance in this comparison since this is normally
far too high by default on every screen. However, that is very easily controlled
through the brightness setting (on most screens) and should not impact the other
areas being measured anyway. It is easy enough to obtain a suitable luminance
for your working conditions and individual preferences, but a reliable factory
setup in gamma, white point and colour accuracy is important and not as easy to
change accurately without a calibration tool.
From these comparisons we can also compare the
calibrated colour accuracy, black depth and contrast ratio. After a calibration
the gamma, white point and luminance should all be at their desired targets.

Default setup of the screen out of the box was
good with a gamma and white point within a few % deviance from the targets.
Colour accuracy was good at dE 2.8 average, and contrast ratio was excellent for an
IPS panel at
1096:1. It
is too bright of course, but that's easy to turn down via the brightness
setting. If we compare those default settings to the new 27"
U2715H model the
results are pretty comparable. That had a slightly worse default gamma (2.3
average, 5% deviance) but a slightly better white point (6414k, 1% deviance).
Colour accuracy was very similar with dE average of 2.7, although contrast ratio out
of the box was not as strong at 928:1. So comparing default screen settings,
there's not much to separate the new 2560 x 1440 resolution 25" and 27" models.


The display was very strong when it came to black depth
and contrast ratio for an IPS-type panel. With a calibrated contrast ratio
of 1138:1 it was the best we had seen to date from this kind of panel
technology. It out-did other recent Dell models like the U2415 (1011:1) which
was impressive and was quite a lot higher than the 27" U2715H (856:1). Of course
it can't compete with VA panel types which can reach over 2000:1 easily, and
commonly up to 3000:1, even close to 5000:1 in the case of the Eizo FG2421.

Viewing Angles

Above: Viewing
angles shown from front and side, and from above and below. Click for
larger image
Viewing angles of the U2515H were very good as you
would expect from an IPS panel. Horizontally there was very little colour tone
shift until wide angles past about 45�. A slight darkening of the image occurred
horizontally from wider angles as you can see above as the contrast shifted
slighting. Contrast shifts were more noticeable in the vertical field
but overall they were very good. The screen offered the wide viewing angles of
IPS technology and was free from the restrictive fields of view of TN Film
panels, especially in the vertical plane. It was also free of the off-centre
contrast shift you see from VA panels and a lot of the quite obvious gamma and
colour tone shift you see from some of the modern VA panel type offerings. All as
expected really from a modern IPS panel.

Above: View of an
all black screen from the side. Click for larger version
On a black image there is a characteristic white
glow when viewed from an angle, commonly referred to as IPS-glow. This is common
on most modern IPS panels and can be distracting to some users. If you view dark
content from a normal head-on viewing position, you can actually see this glow
as your eyes look towards the edges of the screen if the screen is of a large
size. This is not so much of a
problem on a smaller screen like this than it might be on some of the larger displays
like the 27" model for instance, but it could still be distracting if you work with a lot of dark
content. The IPS glow was normal here for a modern IPS-type panel.

Panel Uniformity
We wanted to test
here how uniform the brightness and colour temperature was across the screen, as well as identify any
leakage from the backlight in dark lighting conditions. Measurements of the luminance
and colour temperature were taken at 35 points across the panel on a pure
white background. The measurements for luminance were taken using BasICColor's calibration
software package, combined with an X-rite i1 Display Pro
colorimeter with a central point on the screen calibrated to 120 cd/m2. Measurements for colour temperature (white point) were taken using
BasICColor software and the i1 Pro spectrophotometer which can more accurately
measure the white point of different backlighting technologies. The below uniformity diagram shows the difference, as a percentage,
between the measurement recorded at each point on the screen, as compared with the
central reference point.
It is worth
noting that panel uniformity can vary from one screen to another, and can depend
on manufacturing lines, screen transport and other local factors. This is only a
guide of the uniformity of the sample screen we have for review.

Uniformity of Luminance

The luminance uniformity of the screen was
mostly pretty good. The top corners did
seem to drop down in luminance somewhat, ranging down to 104
cd/m2
in the most extreme cases. The lower middle was also a little bit brighter
than the centrally calibrated point, ranging up to 131 cd/m2 in
the most extreme case. Around 83% of the screen was within a 10% deviance
from the centrally calibrated point which was good.

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version
As usual we also tested the screen with an all
black image and in a darkened room. A camera was used to capture the result. The
camera showed there was very little backlight leakage here with some clouding
detected in the top left hand corner. It was not too bad
though and hard to pick out with the naked eye, and should not present any major problems in normal use.

General and Office Applications
The U2515H is a new screen size we've not tested
before, measuring 25" diagonally. We are starting to see a few manufacturers
adopt this screen size though and it seems to be attracting a lot of interest in
the market. It is a little bit bigger than a 24" model, although noticeably
smaller than a 27" we felt during use. What makes this particularly interesting
is that the screen still offers the same 2560 x 1440 resolution that the wide
range of 27" models provide. Being smaller, it carries a couple of advantages
though. Firstly the retail price is more aligned with the 24" models, and is
considerably cheaper than the 27" equivalents. For example the Dell 24" U2414H
retails for ~�174, the 25" U2515H for ~�254 and the 27" U2715H for ~�416.
Secondly, with the large resolution crammed in to a smaller screen size, you get
a higher DPI, tighter pixel pitch (0.216mm) and a sharper looking image. It
doesn't have the DPI of ultra-HD or 4k displays, but it is a bit different from
a 27" model with the same resolution.
The pixel pitch of 0.216 mm is small as a result,
and by comparison a standard 16:9 format 24" model has a pixel pitch of 0.2745mm and a
27" model has 0.231mm.
Some users may find the small text a little too small to read comfortably, and
we'd advise caution if you are coming from a screen where the pixel pitch and text are much larger.
We have gotten used to 27" displays with 2560 x 1440 and so the change here,
although noticeable, is not extreme. You shouldn't need to worry about operating
system or application scaling like you do on 4k displays, as you can just run at
the native resolution comfortably and take advantage of the nice real estate
offered. You could use scaling options if you found the fonts and texts a bit
too small, but if you are going to do that, you might be better off with the
larger 2560 x 1440 27" models (e.g. U2715H) so you don't have to give up
real-estate. The high resolution is really good for
office and general use, giving you a really big area to work with. It is
a noticeable upgrade from a 24" 1080p or 1200p resolution for sure. For those wanting a
high resolution for CAD, design, photo work etc, this is a really good option.
The image was very sharp and crisp and text was very clear.
With its
WQHD display, you enjoy 77% more desktop space than a full HD screen to spread
out your windows and palettes.
The light AG coating of the new AH-IPS panel is
certainly welcome, and a very positive change from the older grainy and 'dirty'
appearance of older IPS AG coatings, although not used on Dell 27" models since
the U2711 about 5 years ago.
The wide
viewing angles provided by the IPS panel technology on both horizontal and
vertical planes, helps minimize on-screen colour shift when viewed from
different angles.
The default setup of the screen was good in all
regards thanks to the pretty decent factory calibration, and we were also
pleased with the excellent 1138:1 contrast ratio (after calibration).
The brightness
range of the screen was also very good, with the ability to offer a luminance
between 383 and 35 cd/m2. This should mean the screen is perfectly
useable in a wide variety of ambient light conditions, including darkened rooms.
A setting of ~21 in the OSD brightness control should return you a luminance
close to 120 cd/m2 out of the box. On another positive note, the brightness
regulation is controlled without the need for the use of the now infamous
Pulse-Width Modulation (PWM), and so those who suffer from eye fatigue or
headaches associated with flickering backlights need not worry.
There was no
audible noise or buzzing from the screen, even when specifically looking for it
using test images with a large amount of text at once. The screen also remains
cool even during prolonged use. There is a 'paper' preset mode available from
the menu which may be useful if you want to set up the screen for different uses
perhaps and made the image much more yellow. There are only 2x HDMI and 2x
DisplayPort connections (1 regular, 1 mini) here so connectivity could be
considered a little limited for some older systems. We would have liked to have
seen DVI and VGA provided as many graphics cards still rely on these options and
no one wants to have to go and fork out for an adapter cable really.
The screen offers 5x USB 3.0 ports which can be
useful and it was nice to keep this up to date with the modern version. Here, 4 of them are on the underside back with the
video connections, and 1 is on the back of the screen (the charging capable
port) since the profile of the screen is too thin to really make them easy to
include on the edge of the screen.

There are no further extras like ambient light
sensors or card readers which can be useful in office environments. There was a
great range of ergonomic adjustments available from the stand allowing you to
obtain a comfortable position for a wide variety of angles. The VESA mounting
support may also be useful to some people as well. Perhaps one of the biggest
draws for the U2515H (and other new UltraSharp models) is its ultra-thin bezel and narrow edges. This makes it
potentially a great screen for multi-monitor setups and we liked the design of
the new screen.

Above: photo of
text at 2560 x 1440 (top) and 1920 x 1080 (bottom)
The screen is designed to run at its native
resolution of 2560 x 1440 and at a 60Hz recommended refresh rate. However,
if you want you are able to run the screen outside of this resolution. We tested
the screen at a lower 1920 x 1080 resolution to see how the screen handles the
interpolation of the resolution, while maintaining the same aspect ratio of
16:9. At native resolution the text was very sharp and comfortable as we've already
discussed. When running at a 1080p resolution the text is still sharp, with low
levels of blurring. You do lose some screen real-estate as well of course but
the image seems to be interpolated well from 1080p sources.

Responsiveness and Gaming
Quoted G2G Response Time |
6ms G2G (Fast mode)
8ms G2G (Normal mode) |
Quoted ISO Response Time |
n/a |
Panel Manufacturer and
Technology |
LG.Display |
Panel Part |
LM250WQ1-SSA1 |
Overdrive Used |
Yes |
Overdrive Control Available to
User |
'Response Time' |
Overdrive Settings |
Normal, Fast |
The U2515H is rated by Dell as having a 6ms to 8ms G2G response time,
depending on the setting selected,
which indicates the panel uses
overdrive /
response time compensation (RTC) technology to boost pixel transitions
across grey to grey changes. There is user control over the overdrive impulse
within the OSD menu using the 'Response Time' option. The
part
being used is the
LG.Display LM250WQ1-SSA1 AH-IPS panel. Have a read about response time in
our
specs section if you need additional information about this measurement.
We will first test the screen using our thorough
response time testing method. This uses an oscilloscope and photosensor to
measure the pixel response times across a series of different transitions, in
the full range from 0 (black) to 255 (white). This will give us a realistic view
of how the monitor performs in real life, as opposed to being reliant only on a
manufacturers spec. We can work out the response times for changing between many
different shades, calculate the maximum, minimum and average grey
to grey (G2G) response times, and provide an evaluation of any overshoot present
on the monitor.
We use an
ETC M526
oscilloscope for these measurements along with a custom photosensor device.
Have a read of
our response time measurement article for a full explanation of the testing methodology and reported
data.
Response Time Setting Comparison

The U2515H comes with a user control for the
overdrive impulse available within the OSD menu in the 'display' section as
shown above. This isn't something Dell used to provide, but they've started to
feature it on their new models which is pleasing. Previously the user was reliant
on the factory setup and often this has lead to issues with overshoot on some
models (e.g. Dell U2413, U2713H, U3014). There are two options available here in
the menu, for 'normal' and 'fast' modes.
First of all we carried out a smaller sample set
of measurements in both of the 'Response Time' settings. These, along with various
motion tests allowed us to quickly identify which was the optimum overdrive setting
for this screen.

First we tested the screen with the Response Time
option set to 'Normal' which according to Dell should have an 8ms G2G response
time. Response times varied somewhat, with some transitions being a little
slower at around 11 ms, and others reaching down to 6 - 7 ms. Overall we
measured an average 8.2ms G2G response time which was as good as we have seen to
date for an IPS panel. Keep in mind this is based on a small sample set, so the
actual overall average response time might vary when we come to measure a wider
range of transitions. In this response time mode there were a couple of cases
where overshoot was quite high but not a massive amount overall. A decent result
from the 'normal' response time mode.

With the Response Time setting now switched up to the 'Fast'
mode, response times had improved a little to 7.8ms G2G average. However, this
was at the cost of some noticeable overshoot which was a shame. The overdrive
was being applied a bit too aggressively here, trying to reduce response times
further, but introducing too many side-effects sadly. The 'Normal' mode was
optimum on this model we felt as the slight improvement in response times wasn't
worth the high levels of overshoot on more transitions.

If we take some test photos using the PixPerAn
tool you can make some further visual comparisons between the overdrive
'Response Time' settings. With Response Time set to 'normal' the moving image
showed some low levels of motion blur, but nothing too major. There was no sign
of any overshoot artefacts in this mode which was pleasing. When you switch to the 'fast' setting, the
blurring is reduced a little as response times are boosted. Some slight
overshoot is evident in these particular colour transitions but nothing major
here only some slight dark trailing. We know from our
oscilloscope measurements above that some transitions do show significant levels
of overshoot on quite a few transitions so we still prefer the 'normal' mode.
More Detailed Measurements - Response Time =
Normal
Having established that the Response Time 'Normal' mode seemed to
offer the best response/overshoot balance we carried
out our normal wider range of measurements as shown below:



The average G2G response time was more accurately
measured at 9.3ms which was good for an IPS panel overall. Some transitions
were faster at 6 - 7 ms minimum, particularly when changing to white (x >
255) or to black (x > 0). The
rise and fall time average were very similar as well.


There was very little overshoot as well in this
Response Time mode, with only a couple of transitions showing anything
significant.
The overdrive impulse was being applied well and in a controlled fashion which was pleasing.
We had seen that boosting the RTC in the 'Fast' mode just led to too much
overshoot.

Transition: 0-50-0
(scale = 20ms)
The above graph gives an example of the most
severe overshoot
with response time set to 'normal'. On the
rise time in this example, the brightness overshoots the desired level here by
25.9%. Nearly all other transitions showed no overshoot at all which was very
good.

Display Comparisons


The above comparison table and graph shows you the
lowest, average and highest G2G response time measurement for each screen we
have tested with our oscilloscope system. There is also a colour coded mark next
to each screen in the table to indicate the RTC overshoot error, as the response
time figure alone doesn't tell the whole story.
The response time performance of the U2515H using
the 'Normal' Response Time setting was good overall for an IPS-type panel. With an
average G2G response time of 9.3ms measured, it was a little slower than our
reference point IPS screen, the Dell U2415 (8.6ms G2G). That represented about as good as you can get from
modern IPS response times to date, without introducing much in the way of overshoot at
all.
The 'Fast' Response time mode pushed pixel
transitions faster, but did result in some significant overshoot so should
probably be avoided. Some IPS
models can reach lower response times, like the
Dell U2713H for instance (7.2ms)
but not without the cost of very high overshoot. In practice there was not much
really to separate any of the recent Dell models, with the U2515H being pretty
comparable to the U2414H (8.9ms) and U2715H (9.9ms). Modern TN Film panels are still
much faster, reaching down to 2.9ms for instance in the example of the new
Asus
ROG Swift PG278Q (with moderate overshoot).
The screen was also tested using the chase test in
PixPerAn for the following display comparisons. As a reminder, a series of
pictures are taken on the highest shutter speed and compared, with the best case
example shown on the left, and worst case example on the right. This should only
be used as a rough guide to comparative responsiveness but is handy for a
comparison between different screens and technologies as well as a means to
compare those screens we tested before the introduction of our oscilloscope
method.

25"
8ms
G2G LG.Display AH-IPS (Response Time = Normal)
In practice the Dell U2515H performed best with
Response Time set to 'normal'. There were low levels of motion blur and no
ghosting visible, with the moving image looking pretty sharp. Thankfully no
overshoot was detectable at all which was pleasing as well.

25"
8ms
G2G LG.Display AH-IPS (Response Time = Normal)

27"
8ms
G2G LG.Display AH-IPS (Response Time = Normal)

24"
8ms
G2G LG.Display AH-IPS (Response Time = Normal)

23.8" 8ms G2G
LG.Display AH-IPS
Comparing the U2515H against the other recent
UltraSharp screens showed very comparable performance overall. The higher
resolution 25" and 27" models were ever so slightly slower than the 24" models,
and had a bit of minor overshoot on a few transitions. Nothing significant to
separate the four models here though in day to day use.

25"
8ms
G2G LG.Display AH-IPS (Response Time = Normal)

27"
1ms
G2G AU Optronics TN Film @ 144Hz (OD = Normal)

27" 1ms G2G
AU Optronics TN Film + 144Hz (AMA = High)

23.5" 4ms G2G
Sharp MVA + 120Hz
We've also included a comparison above against
3 very fast 120Hz+ compatible screens we have tested. The other screens shown
here are all aimed primarily at gamers and have various features and extras
which make them more suitable overall for gaming.
Firstly there is a comparison against the
Asus ROG Swift PG278Q with its 144Hz refresh
rate and fast response time TN Film panel. This showed very fast pixel response times and smooth movement thanks to
its increased refresh rate. You are able to reduce the motion blur even more
through the use of the ULMB strobed backlight as well if you need to. In other
related areas this screen also supports NVIDIA's G-sync technology. There was
some slight overshoot noticeable on the Asus but nothing major.
Then there is a comparison against the
BenQ XL2720Z with another very fast TN Film panel and 144Hz refresh rate.
This showed very low levels of motion blur, but some dark overshoot was
introduced as a side-effect as you can see. This screen even includes a native
Blur Reduction mode to help eliminate further perceived motion blur.
Lastly there is the MVA based Eizo FG2421 screen
with a fast response time (especially for the panel technology being used) and
120Hz refresh rate support. There is also an additional 'Turbo 240' motion blur
reduction mode which really helps reduce the perceived motion blur in practice.
While these pixel response tests from PixPerAn
give one view of the performance of the panel, there is something else going on as well here which can't be picked out by the camera. All of these other
gaming models are
running at 120Hz (or higher) refresh rates, which allows for improved 120fps+ frame rates and
in some cases the support of
3D stereoscopic content as well. This can really help improve smoothness and
the overall gaming experience so these screens still have the edge when it comes
to fast gaming. Any additional extras to reduce perceived motion blur can also
have a real benefit in practical terms, and again not easy to pick out with this
camera method.

The overall gaming performance of the Dell U2515H
was good and we were pleased with what Dell have done with the response time
control on these new UltraSharp range models. The two response time settings allow you to choose the
best option for your needs. The 'normal' mode was our preferred option, giving a
reasonably fast (for IPS) response time of 9.3ms G2G, without introducing any
significant overshoot. It is a
screen lacking higher refresh rate support or any advanced gaming features like
blur reduction modes or G-sync/FreeSync, but as a general screen with decent IPS gaming
performance, it's decent. It was pretty comparable at the end of the day with
the 24" and 27" equivalents which is not a bad thing at all. The 27" U2715H
offers a larger screen size so might provide a little more immersion in gaming
than this smaller 25" screen, but the cost is quite a bit higher.

Additional Gaming Features

Aspect Ratio Control -
Like the U2414H and U2715H models, the U2515H has 3 options for
aspect ratio control through the OSD 'Display' menu as shown above. There
are options for wide 16:9, 5:4 and 4:3 only. There is no 1:1 pixel mapping mode
specifically but given a lot of content from external devices is 16:9 aspect
ratio by default, the native aspect of the screen can at least accommodate that
nicely. You will have to put up with the screen interpolating 1080p content up
to the full size of the screen when using an external device, as you can't use
any kind of 1:1 scaling option on this model.

Preset Modes -
There is a specific 'game' available in the
OSD which appears to make the image a little cooler than our calibrated custom
mode. It gives you access to the dynamic contrast ratio control if you want to
use it as well.

Lag
We have written an in depth article about
input lag and the various measurement techniques which are used to evaluate
this aspect of a display. It's important to first of all understand the
different methods available and also what this lag means to you as an end-user.
Input Lag vs. Display Lag vs. Signal
Processing
To avoid confusion with different terminology we
will refer to this section of our reviews as just "lag" from now on, as there
are a few different aspects to consider, and different interpretations of the
term "input lag". We will consider the following points here as much as
possible. The overall "display lag" is the first, that being the delay between
the image being shown on the TFT display and that being shown on a CRT. This is
what many people will know as input lag and originally was the measure made to
explain why the image is a little behind when using a CRT. The older stopwatch
based methods were the common way to measure this in the past, but through
advanced studies have been shown to be quite inaccurate. As a result, more
advanced tools like SMTT provide a method to measure that delay between a TFT
and CRT while removing the inaccuracies of older stopwatch methods.
In reality that lag / delay is caused by a
combination of two things - the signal processing delay caused by the TFT
electronics / scaler, and the response time of the pixels themselves. Most
"input lag" measurements over the years have always been based on the overall
display lag (signal processing + response time) and indeed the SMTT tool is
based on this visual difference between a CRT and TFT and so measures the
overall display lag. In practice the signal processing is the element which
gives the feel of lag to the user, and the response time of course can
impact blurring, and overall image quality in moving scenes. As people become
more aware of lag as a possible issue, we are of course keen to try and
understand the split between the two as much as possible to give a complete
picture.
The signal processing element within that is quite
hard to identify without extremely high end equipment and very complicated
methods. In fact the studies by Thomas Thiemann which really kicked this whole
thing off were based on equipment worth >100,1000 Euro, requiring extremely high
bandwidths and very complicated methods to trigger the correct behaviour and
accurately measure the signal processing on its own. Other techniques which are
being used since are not conducted by Thomas (he is a freelance writer) or based
on this equipment or technique, and may also be subject to other errors or
inaccuracies based on our conversations with him since. It's very hard as a
result to produce a technique which will measure just the signal processing on
its own unfortunately. Many measurement techniques are also not explained and so
it is important to try and get a picture from various sources if possible to
make an informed judgement about a display overall.
For our tests we will continue to use the SMTT
tool to measure the overall "display lag". From there we can use our
oscilloscope system to measure the response time across a wide range of grey to
grey (G2G) transitions as recorded in our
response time
tests. Since SMTT will not include the full response time within its
measurements, after speaking with Thomas further about the situation we will
subtract half of the average G2G response time from the total display lag. This should allow us to give a good estimation of
how much of the overall lag is attributable to the signal processing element on
its own.
Lag Classification
To help in this section we will also introduce a broader classification system
for these results to help categorise each screen as one of the following levels:
-
Class 1)
Less than 16ms / 1 frame lag - should be fine for gamers, even at high levels
-
Class
2)
A lag of 16 -
32ms / One to two frames - moderate lag but should be fine for many gamers.
Caution advised for serious gaming and FPS
-
Class
3)
A lag of more
than 32ms / more than 2 frames - Some noticeable lag in daily usage, not
suitable for high end gaming

For the full reviews of the models compared here and the dates they were written
(and when screens were approximately released to the market), please see our
full
reviews index.
(Measurements in ms) |
|
Total Display Lag (SMTT
2) |
13.7 |
Pixel Response Time
Element |
4.65 |
Estimated Signal
Processing Lag |
9.05 |
Lag Classification |
1 |
|

Class
1 |
We have provided a comparison above against other
models we have tested to give an indication between screens. The screens
tested are split into two measurements which are
based on our overall display lag tests (using SMTT) and half the average G2G
response time, as measured by the oscilloscope. The response time is split from
the overall display lag and shown on the graph as the green bar. From there, the
signal processing (red bar) can be provided as a good estimation.
The screen showed a total average display lag of
13.7 ms as measured with SMTT 2. Taking into account half the average G2G
response time at 4.65ms ('Normal' Response Time setting), we can estimate that
there is ~9.05 ms of signal
processing lag on this screen. This is nice and low and should not present any
problems for gaming, even playing fast FPS games. It's ever so slightly more
than the U2415 and U2715H models, but only by ~2ms so nothing to worry about.

Movies and Video

The following summarises the screens performance
in video applications:
-
25"
screen size makes it a fairly small option nowadays for an all-in-one multimedia screen,
much smaller than LCD TV's and many larger format desktop monitors
which are now emerging. The 27" U2715H would offer you a slightly bigger
screen for movies.
-
16:9
aspect ratio is well suited to videos and movies, leaving
you with smaller/no borders on DVD's and wide screen content at the top and
bottom than on a 16:10 aspect display.
-
2560 x
1440 resolution can support full 1080 HD resolution content.
-
Digital interfaces support HDCP for any encrypted and protected content
-
HDMI and DisplayPort
connections available. Nice to see HDMI connectivity included for modern DVD
players, Blu-ray, consoles etc. 2 HDMI ports are available on this model. MHL
support if you want to play content mirrored from your mobile devices.
-
Cables provided in the box
for DisplayPort to Mini DisplayPort only, no HDMI cable is provided.
-
Light
AG coating provides clear images with no major graininess, and without the
unwanted reflections of a glossy solution.
-
Wide
brightness range adjustment possible from the display, including high maximum
luminance of ~383
cd/m2 and a good minimum luminance of
35 cd/m2. This should afford you very good control for different
lighting conditions. Contrast ratio remains stable across most of that adjustment
range as well and is excellent for an IPS-type panel. Brightness regulation is controlled
without the need for PWM and so is flicker free at all settings which is
pleasing.
-
Black
depth and contrast ratio are excellent for an IPS-type panel at 1138:1 after
calibration. Detail in darker scenes should not be lost as a result.
-
There
is a specific 'movie' preset mode available for movies or video in the OSD
which looked a lot cooler and more blue than our calibrated custom mode.
-
Good
pixel responsiveness which can handle fast moving scenes in movies without
issue. No overshoot issues when sticking to the 'normal' response time mode
which is great news.
-
Wide viewing angles from IPS panel technology
meaning several people could view the screen at once comfortable and from a
whole host of different angles. White glow from an angle on black content may
be problematic to some users and is common for IPS panel technology.
-
No
real backlight leakage on our sample which is good.
-
Wide range of ergonomic adjustments available
from the stand, allowing you to adjust the screen to suit varying viewing
positions.
-
No integrated stereo speakers offered on this model, but it is compatible with
Dell's SoundBar if you want. There is also an audio out connection if you want
to connect to headphones or separate speakers when sending sound to the screen
over HDMI.
-
Hardware aspect ratio control options should be adequate given the default
aspect ratio of the screen is 16:9. Additional 5:4 and 4:3 modes offered as
well.
-
Picture By Picture (PbP) or Picture In Picture (PiP) are not available on
this model.

Conclusion
Readers won't be disappointed to hear that the
U2515H compares very well to the other recent Dell UltraSharp screens. It is
very similar overall to the smaller 24" U2414H / U2415 and 27" U2715H models.
The feature set, spec, connections and design are basically identical which make
it an interesting intermediate screen size.
Performance wise the default setup and factory
calibration were good, although you will want to stick with the 'standard' mode
unless you have a calibration device. We were impressed with the high contrast
ratio for an IPS-type panel as well, outdoing the 27" U2715H by a fair amount.
Response times were low for an IPS panel and there was pretty minimal overshoot
too. Signal processing lag was also nice and low, keeping in line with the other
recent UltraSharp screens. Dell seem to have IPS gaming refined at the moment
with the current range of 60Hz panels. The light AG coating and flicker free
backlight were very welcome, again much like on the other new models.
The most attractive thing about the new U2515H is
its price point, being only slightly more expensive than the 24" models, but
offering a higher 2560 x 1440 resolution. It's also quite a lot cheaper than the
27" equivalents so it's bound to be a popular screen. The pixel pitch is small,
although we didn't find it a problem for day to day use without any operating
system scaling. We are used to using the 2560 x 1440 27" models though, so we
would just advise some caution if you're coming from a larger pixel pitch
screen. It might take a bit of getting used to, but the DPI is actually pretty
nice on this size screen we felt. As long as you don't mind the slightly smaller
screen size and smaller fonts, the U2515H is an excellent screen and at such a
lower cost than the U2715H it's a great option.
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Pros |
Cons |
Nice low cost while still
offering 2560 x 1440 resolution of the larger 27" models |
Missing DVI and VGA
connections, may be limited for some |
Good default factory setup and
excellent contrast ratio for an IPS panel |
IPS glow at normal levels, had
maybe hoped for low-glow like recent U2414H |
Good response times and low
lag |
Caution advised with small
pixel pitch for some users. |


Dell U2515H Now Available

|
TFT Central Awards Explained
We have two award
classifications as part of our reviews. There's the top 'Recommended'
award, where a monitor is excellent and highly recommended by us. There is
also an 'Approved' award for a very good screen which may not be perfect,
but is still a very good display. These awards won't be given out every
time, but look out for the logo at the bottom of the conclusion. A list of
monitors which have won our awards is available
here. |