Introduction

There's been a fair few new Ultra-wide 21:9 aspect ratio screens released by various manufacturers and it's an interesting option in the desktop monitor market. We remember looking at the Dell U2913WM back in early 2013 which was one of the first 21:9 format displays released, offering a 29" diagonal and 2560 x 1080 resolution. Nowadays people are after something even bigger and there's been a fair few 34" sized models released with 3440 x 1440 resolutions. We took a look at one such model in September 2014 when we reviewed the LG 34UM95. We found the ultra-wide format quite appealing for day to day use and although it's an odd feeling when you first use one, you soon get used to it. Since then we've seen a couple of manufacturers delve into another new area of displays, releasing 34" ultra-wide models but with a slightly curved shape to them. Much like you can get with some LCD TV's, curved desktop monitors seems to be a new trend manufacturers are exploring. Dell have bypassed releasing a flat 34" ultra-wide model, and instead progressed straight to releasing the new curved U3415W which we have with us now for testing. We are keen to see how we get on with the curved nature of the screen and how this screen performs overall in our tests. Incidentally we are testing the A01 revision here.

Dell's website states: "Discover one of the world’s first 86.5 cm (34") 21:9 curved monitors with a panoramic view, cinematic WQHD resolution and superb sound. An immersive panoramic experience: The Dell UltraSharp 86.5 cm (34") Curved Monitor engages you in a new wrap-around viewing experience with a 21:9 ultra-wide curved screen that offers more display area and enhanced viewing comfort."

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Dell U3415W Now Available
 

Specifications and Features

The following table gives detailed information about the specs of the screen:

The U3415W offers a good range of modern connectivity options which are similar to other recent UltraSharp screens. There are 1x HDMI 2.0, 1x 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. Cables are provided in the box for DP > Mini DP and HDMI.

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, 4x USB 3.0 ports (with 2x upstream connections) and an audio out port (headphones not supported). The screen also has 2x 9W stereo speakers (rare for Dell screens), Picture In Picture (PiP) and Picture by Picture (PbP) support and a uniformity compensation mode.

Below is a summary of the features and connections of the screen:

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 volume control from button 1, input selection 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.

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

The menu is split in to 11 sections shown down the left hand side, with the options relevant to each section then shown on the right. The first section gives you access to the brightness and contrast functions as shown above. You will notice the familiar Dell energy bar in the top right hand corner as well, showing your power consumption and a useful quick indicator to your brightness level in fact.

The second section allows you to switch between video input source.

The third 'color' section has a few options relating to the colour setup, including most notably access to the preset mode menu shown above.

The 'Display' section has a few useful features. There are options for the hardware level aspect ratio control at the top, with settings for wide 21:9, wide 16:9, auto resize and 1:1 available. You can also access the response time control here, and the uniformity compensation function.

The next menu allows you to control the Picture By Picture (PbP) and Picture In Picture (PiP) functions as shown. Have a look at the user manual online for more info about available configurations.

The 'USB selection' menu allows you to choose the video input which will link you back to a specific PC for USB functionality. With 2x USB upstream ports on the screen you can connect the display back to two PC's if you need to, and then choose which PC is active via the menu when using different video inputs.

The audio menu allows you to control the speaker volume and input source.

The 'Energy' menu controls a couple of power saving features as shown.

The 'Menu' section allows you to adjust the OSD menu itself.

The 'personalize' section allows you to customise what quick access options are available, depending on what you need to access most often. A Useful feature.

Finally the 'others' section has a few options including allowing you to turn the button sound on/off.

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. 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 55W and less than 0.5W in standby. They also list maximum power usage of 130.0W (*) but this is with maximum brightness, Dell SoundBar and USB connected also. We carried out our normal tests to establish its power consumption ourselves.

We tested this ourselves and found that out of the box the screen used 48.3W at the default 75% brightness setting. Once calibrated the screen reached 32.1W consumption, and in standby it used only 0.5W. We have plotted these results below compared with other screens we have tested for reference.

Panel and Backlighting

Panel Part and Colour Depth

The Dell U3415W features an LG.Display LM340WU2-SSA1 AH-IPS panel which is capable of producing 1.074 billion colours. As we understand it the panel offers an 8-bit colour depth with additional Frame Rate Control (FRC) stage added to support 10-bit content. Keep in mind whether this is practically useable and whether you're ever going to truly use that colour depth. You need to have a full 10-bit end to end workflow to take advantage of it which is still quite expensive to achieve and rare in the market, certainly for your average user. This includes relevant applications and graphics cards as well, so to many people this 10-bit support might be irrelevant. The part is confirmed when dismantling the screen. Incidentally we are testing the A01 revision here.

Screen Coating

The screen coating on the U3415W 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 Dell offerings like the U2715H and U2515H for instance. Thankfully it isn't a heavily grainy coating like some old IPS panels feature, including some old Dell models circa 2011. 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 slight cross-hatching patterns visible on the coating when you inspect it closely, but not to the extent that you can see on the U2713HM which was known for this issue affecting some users.

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.

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, much like many of Dell's other recent screens. Oddly they don't advertise this as a selling point, but they probably should as it's a positive thing.

For an up to date list of all flicker-free (PWM free) monitors please see our Flicker Free Monitor Database.

 

Contrast Stability and Brightness

The brightness control gave us a very good range of adjustment. At the top end the maximum luminance reached 300.22 cd/m² which was high, and spot on in fact with the specified maximum brightness from the manufacturer. There was a decent 284.37 cd/m² adjustment range in total, and so at the minimum setting you could reach down to a low luminance of 15.85 cd/m². This should be more than adequate for those wanting to work in darkened room conditions with low ambient light. A setting of 28 in the OSD menu should return you a luminance of around 120 cd/m² at default settings in the Standard preset mode. 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 a linear relationship as the brightness adjustments between settings of 80 and 0 control a steeper luminance range than settings between 100 and 80 as you can see.

The average contrast ratio of the screen was excellent for an IPS panel with an average of 1146:1. This was pretty stable across the brightness adjustment range as shown above although at the lowest brightness settings 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 U3415W comes factory calibrated, showing their focus on providing a high quality product suitable for colour critical work. The screen is packaged with a calibration report unique to your screen, 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:

Dell U3415W - Default Settings / Factory Calibration

  

 

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 75% brightness setting. Colour balance and gamma 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 over-coverage in some blue and red shades, and 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 small 1% deviance from the target which was excellent. White point was measured at 6470k being <0.5% out from the target of 6500k which was again very pleasing.

 

 

Luminance was recorded at a bright 292 cd/m² which is too high for prolonged general use. The screen was set at a default 75% 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 0.26 cd/m² at this default brightness setting, giving us an excellent (for a IPS panel) static contrast ratio of 1134:1. Colour accuracy was good out of the box as well with a default dE average of 2.0, although a maximum of 5.2 showed there were some errors. Testing the screen with various gradients showed smooth transitions with no sign of any banding thankfully. There was some gradation evident as you will see from most monitors in darker tones. Overall the default setup was very good, with the gamma and white point being well configured out of the box, and the screen also offering a low dE. Looks like the factory calibration does provide a reliable setup for the screen which should be fine for most users once they've adjusted the brightness setting. Good work Dell.

 

 

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.

 

Dell U3415W - Calibrated Settings

   

 

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 minor 1% deviance we'd seen out of the box in the 'standard' preset mode. The white point was maintained at the target, now measured at 6501k, but that was already reliable out of the box. Luminance had been improved thanks to the adjustment to the brightness control and was now being measured at 120 cd/m². You may note that you need a higher brightness setting to reach this level in this 'custom color' preset mode than in the 'standard' mode. This left us a black depth of 0.11 cd/m² and maintained an excellent static contrast ratio (for an IPS panel) of 1091:1. Colour accuracy of the resulting profile was very good, with dE average of 0.4 and maximum of 0.8. 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 very good with a gamma within only 1% deviance from the target and white point being <0.5% out. Colour accuracy was good as well thanks to the factory calibration with dE 2.0 average. Contrast ratio was also excellent for an IPS panel at around 1134:1 out of the box. It is too bright of course, but that's easy to turn down via the brightness setting. This factory calibration was a little better than other recent factory calibrated UltraSharp screens from Dell, which showed a little more error from the targets in the table above. We were impressed by the factory setup here on the U3415W.

 

 

 

The display was also very strong when it came to black depth and contrast ratio for an IPS-type panel. With a calibrated contrast ratio of 1091:1 it was very comparable to the LG 34UM95 34" flat format screen (1064:1). It was not quite as high as we'd seen from some other recent smaller screens from Dell, like the U2515H (1138:1) for instance, but it was still very good. Of course it can't compete with VA panel types which can reach over 2000:1 easily, and commonly up to 3000:1, even a little over 4000:1 in the case of the 40" Philips BDM4065UC.

 

Viewing Angles

Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the U3415W 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 slightly 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-type 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. Because of the sheer horizontal size of this 34" panel, the glow towards the edges is more obvious than on small screens, where there isn't such a long distance from your central position to the edges. Some people may find this problematic if they are working with a lot of dark content or solid colour patterns. In normal day to day uses, office work, movies and games you couldn't really notice this unless you were viewing darker content. If you move your viewing position back, which is probably likely for movies and games, the effect reduces as you do not have such an extreme angle from your eye position to the screen edges. The glow effect was a little less than on flat 34" ultra-wide screens as the curved nature created a smaller angle between your eyes and the edges of the screen.

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 36 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
Uniformity Compensation = Off

The luminance uniformity of the screen was moderate here. The left and right hand edges were a bit darker than the central areas of the screen, dropping down to 96 cd/m² in the most extreme cases (-25%). The central areas were a bit more uniform though. Approximately 67% of the screen was within a 10% deviance of the centrally calibrated point which was reasonable.

 

Uniformity Compensation Feature

Like on some of the high end UltraSharp models the U3415W features a uniformity compensation feature within the OSD menu as shown above. This isn't something Dell have made much fuss of oddly, but it's a feature again normally reserved for pro-grade screens. We've seen similar technologies used on NEC and Eizo screens in the past with some positive results. Dell have used it in the past on models like the U2413, U2713H, U3014 and UP3214Q, but not on recent more mainstream UltraSharps like the U2414H, U2415 or U2715H.

We had seen from the U2713H testing that this uniformity compensation mode seemed to do nothing in reality to change the actual performance of the screen. When switching to the "calibrated" mode you could see a visible change in the brightness of the screen but when verifying the variations across the screen with a colorimeter, no improvements had been made. This was a disappointment certainly, especially when we then later tested the Dell U2913WM which had the same feature which seemed to work pretty well. When we then tested the feature on the U2413 and U3014 we found it did help improve the already pretty decent luminance uniformity of the screen but concluded it was largely pointless in practice. It could not be used in the factory calibrated preset modes (Adobe RGB and sRGB), or in the hardware calibrated modes (CAL1 and CAL2) which are surely the modes most users are going to use. If you then wanted to use it in one of the other modes (e.g. standard preset), you had to have the screen at a bright 50% brightness setting, and you cannot change it from this. So really it was pretty useless in real use. It's a shame, and it seemed a very odd choice really considering the type of screen these models are.

Thankfully when we later tested the UP3214Q Dell had made a few improvements to its use, although it still wasn't perfect. The uniformity compensation feature could be used in the standard, color temp and custom color modes only. Again, as with the other models it cannot be used in the factory calibrated sRGB of Adobe RGB modes, or in your hardware calibrated CAL1 or CAL2 modes. This in itself severely limits its practical usage. When using the feature in any of the three preset modes we mentioned, you can at least enable it no matter what brightness setting you are at. You no longer need to revert to the default and overly bright 50% brightness, and instead it can be activated at whatever brightness setting you have set the screen to already. Once enabled in the 'standard' or 'color temp' presets, the brightness and contrast options are then locked so you cannot change away from your setting without first turning the uniformity compensation feature off. At least you have some flexibility to use the feature at differing brightness settings though. When using the 'custom color' preset mode, you CAN change the brightness even with the feature active, so that gives you even more flexibility thankfully in that mode. All of this does mean that you can only use the feature when using the screens native colour space, and there's no way to use sRGB or the Adobe RGB emulation modes and have uniformity compensation active at all.
 

With the feature included again now on the U3415W we were keen to see how it worked, and if it offered any benefits in improving the uniformity of the screen. The option was available when using the standard, colour temp and custom color preset modes only. It was greyed out when using the other preset modes like game or movie. Once enabled the brightness and contrast controls become locked which is a shame, so you are stuck at whatever luminance Dell have decided to lock this at. If you look in the OSD menu you can see the energy bar indicator is at maximum, suggesting the backlight is turned up to full, but then digital white level adjustments are made to provide the uniformity compensation and also reduce the luminance output. We measured the luminance in the standard preset mode at ~174 cd/m² so it was certainly much lower than the maximum brightness of 300 cd/m², but still quite bright compared with a recommended 120 cd/m² level.

If we stick to the standard preset mode for now, we can compare the before and after impact of this feature on the setup of the screen.

Dell U3415W - Default standard preset mode
Uniformity compensation = Off

   

Above is out out of the box default setup discussed earlier in the review, with the uniformity compensation feature turned off. Brightness is set at the default 75 setting in the OSD.

 

Dell U3415W - Default standard preset mode
Uniformity compensation = On

   

Turning the uniformity compensation feature on brought about a few changes to the image. Firstly, the luminance output was dimmed quite a lot, and we measured the brightness now at 174 cd/m². The brightness setting in the OSD cannot be changed, and the power indicator bar shows full energy usage suggesting it was turned up to 100 in reality. So the reduced luminance here is now down to digital white level adjustments. Because of this, the contrast ratio is crushed a lot, down from 1134:1 to 629:1. Not too severe, but certainly a big drop. Most uniformity compensation features from all manufacturers will lead to some loss in contrast ratio. Other aspects of the setup were not affected much, although gamma increased a little to 2.3 average, increasing the error a few percent.

 

Dell U3415W - Calibrated Custom Color preset mode
Uniformity compensation = Off

   

We also tested the before and after performance from our calibrated 'custom color' preset mode. Above is the calibrated result from earlier on in the review.
 

Dell U3415W - Calibrated Custom Color preset mode
Uniformity compensation = On

   

Oddly in the 'custom color' preset mode the uniformity compensation feature had a massive impact to the image appearance, and this is without changing any other aspects of our calibrated screen state. You could spot a noticeable change in the gamma of the screen when the setting was first enabled, and we measured the average gamma now as 2.7, leaving a bit 21% deviance. Luminance had again been suppressed down to 160 cd/m² through the digital white level adjustments, leaving us again with a crushed contrast ratio of only 593:1, compared with the 1091:1 we had before. Colour accuracy was also now way off as well because of the adjusted gamma, with dE average 3.9, maximum of 8.9. We would suggest sticking to the standard preset mode if you're going to use the uniformity compensation feature. In the OSD you can actually have the feature turned on or off for different preset modes which is quite handy, and it remembers what you last had selected if you go back to that preset mode again.

 

Let's have a look how it affects the actual uniformity of the screen as well:

Uniformity of Luminance
Uniformity Compensation = On

With the compensation feature turned on, the luminance uniformity was much better and extremely good in fact. There was very little deviance across the whole screen with only minor differences measured of a few percent. All of the screen was within 5% of the central point of the screen. The feature worked well at correcting the luminance uniformity, although it was a shame it wasn't a bit more flexible.

 

It seems that the uniformity compensation mode makes a mess of the custom color preset mode, so if you do want to use it, stick with the standard preset mode. It doesn't impact the setup in the standard mode much, other than crushing the contrast ratio by a significant amount. You do have to live with a locked brightness as well and a luminance output of ~174 cd/m² which is a bit of a pain.

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 some backlight leakage here with some clouding detected in the corners, particularly the top left. This could be noticed with the naked eye as well, so if you are working with a lot of dark content, or in darkened room conditions this may be a bit distracting. It wasn't major leakage, but there was some there.

 

General and Office Applications

One of the key selling points of ultra-wide screens like the U3415W is it's high resolution and large screen size. The 3440 x 1440 display offers a sharp but comfortable picture. Its pixel area is about 1.8 times larger than an Ultra-Wide Full HD 21:9 monitor, and about 2.4 times larger than a Full HD 16:9 monitor. It provides an efficient environment in using Microsoft Office programs showing 47 columns and 63 rows in excel. Thankfully the high resolution is of a very comfortable size on the 34" panel, with a 0.2325mm pixel pitch is is very comparable to a 27" 2560 x 1440 monitor (0.2331mm). This means you are basically getting a wider desktop to work with, with a similar font size to a 27" model, and maintaining the same vertical resolution as well. If you're coming from a lower resolution / larger pixel pitch you may still find the fonts look quite small to start with, but like the 27" 1440p models out there you soon get used to it. Side by side multi-tasking on this screen is excellent and you really do have a nice wide area to work with. We liked the curved format of the display actually for day to day office work. It just felt a bit more comfortable than a flat screen on a model as wide as this, bringing the corners a bit nearer to you. You didn't really notice the curve in normal use but we liked the feel. Probably down to user taste, so if in doubt try and see one in person.

The light AG coating of the IPS panel doesn't produce any graininess to the image like some aggressive AG solutions can and so white office backgrounds look clean and clear. The wide viewing angles of the IPS panel technology provide stable images from different angles, meaning you can use the screen if you want for colour critical work, photos etc. This panel technology still offers the widest viewing angles and so is well-suited to colour work. Some contrast shifts and IPS-glow may be evident because of the very wide size of the display, as you glance towards the edges from a centrally aligned position. That's hard to avoid on such a large desktop monitor from close up, even with IPS technology. The default factory calibration setup of the screen was very good in all regards, and we were also pleased with the strong 1089:1 contrast ratio (after calibration) as well.

The brightness range of the screen was also very good, with the ability to offer a luminance between 300 and 16 cd/m². This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms. A setting of ~28 in the OSD brightness control should return you a luminance close to 120 cd/m² out of the box in the standard preset mode. 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. All of the recent Dell screens we've tested have been flicker free, so it's a wonder they don't start advertising this as a key feature really, as everyone else seems to be focusing on it.

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.

The screen offers 4x USB 3.0 ports which can be useful and it was nice to keep this up to date with the modern version. Here, 3 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. The screen even has the ability to be connected back to two different PC's using the dual USB upstream connections, meaning you can use the USB hub from two different inputs to the screen if you want to. There are integrated 2x 9W stereo speakers which are reasonable for the occasional YouTube clip or mp3. An additional audio-out connection is provided, although oddly it doesn't support headphones and Dell haven't provided a headphone port here.

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. The thin bezel and edge design of the screen make it a possibility for multi-monitor setups, although the sheer size of it might make that difficult for most people. You need one massive desk to cope with 2x 34" ultra-wide screens!

 
Above: photo of text at 3440 x 1440 (top) and 2560 x 1080 (bottom)

The screen is designed to run at its native resolution of 34400 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 2560 x 1080 resolution to see how the screen handles the interpolation of the resolution, while maintaining the same aspect ratio of 21:9. At native resolution the text was very sharp and comfortable as we've already discussed. When running at a the lower resolution the text is still pretty sharp, with low levels of blurring. You do lose a lot of screen real-estate as well of course but the image seems to be interpolated well.

Responsiveness and Gaming

The U3415W is rated by Dell as having a 5ms 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 LM340WU2-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 U3415W 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 quite a bit slower at around 12 - 15ms, and some even reaching as high as 20ms. Others transitions were faster, reaching down to 6 - 7ms and living up to the spec at least. Overall we measured an average 10.3ms G2G response time which was moderate for an IPS panel, but not as fast as we'd seen from other recent Dell models like the 24" U2415 for instance (8.6ms with response time 'normal'). In this response time mode there was very little overshoot at all across any transition so there were no annoying dark or pale halos like you might see where overshoot is at a higher level. We had perhaps hoped for a little faster performance here given our recent experience with Dell screens. Let's see if the 'Fast' mode can offer any improvements at all.

With the Response Time setting now switched up to the 'Fast' mode, response times had improved quite a lot down to 7.1ms G2G average. However, this was at the cost of some very noticeable overshoot which was too high to make it practical for most uses. The overdrive was being applied too aggressively here, trying to reduce response times, but introducing too many side-effects sadly. The 'Normal' mode was optimum on this model we felt. This was a shame as we had hoped for faster response times here, but without the overshoot problems which had been introduced. Maybe somewhere in the middle would have been a better balance, reaching down to around 8.5ms G2G would have been nice without overshoot, as quite a few other good 60Hz IPS screens have managed in recent times. You're better sticking with the 'normal' mode here to avoid the noticeable overshoot.
 

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 noticeable amount and the image becomes sharper as response times are boosted. However, some noticeable overshoot is evident in these particular colour transitions in the form of obvious dark trailing. We know from our oscilloscope measurements that a fair few transitions show significant levels of overshoot so we 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 10.6ms which was moderate for an IPS panel overall. Some transitions were faster at as low as 6ms minimum, particularly when changing to white (x > 255). The rise times were a fair bit slower than the fall times on average, with a few problematic transitions which were quite a lot slower. These were most noticeable when changing from black to dark grey.

There was pretty much no overshoot as well in this Response Time mode, with only a couple of transitions showing anything at all, and even then, fairly low. 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.

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 U3415W using the 'Normal' Response Time setting was moderate overall for an IPS-type panel. With an average G2G response time of 10.6ms measured, it was a little slower than some other recent Dell screens like the U2515H (9.3ms) and U2715H (9.9ms), although not by a huge amount. Our reference point for a 60Hz IPS panel is the Dell U2415 (8.6ms) which until recently was the best we had seen from an IPS panel without introducing a lot of overshoot. The new Acer XB270HU with a 144Hz IPS-type (AHVA) panel had reached a very impressive 5.5ms G2G without overshoot, although that screen operates at a much higher refresh rate than the U3415W of course. The 'Fast' Response time mode pushed pixel transitions faster, but did result in some significant overshoot so should probably be avoided. Modern TN Film panels are still much faster, reaching down to 2.9ms for instance in the example of the 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.

34" 8ms G2G LG.Display AH-IPS (Response Time = Normal)

In practice the Dell U3415W performed best with Response Time set to 'normal'. There were pretty low levels of motion blur and no ghosting visible. Thankfully no overshoot was detectable in these tests which was pleasing and we know from our oscilloscope measurements that there's very little in this response time mode.

34" 8ms G2G LG.Display AH-IPS (Response Time = Normal)

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

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

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

We can start by comparing the U3415W against other recent Dell UltraSharp screens in sizes between 24 and 27". In practice the U3415W was very close to the U2715H model, with response times being only slightly slower. There were comparable levels of blurring to the moving image there. The 25" U2515H was a tad faster, but not by much. The 24" U2415 showed a sharper moving image than the U3415W and also had a slightly lower level of overshoot as well. That model represents about as good as you can get from a modern 60Hz IPS panel without overshoot being introduced.

34" 8ms G2G LG.Display AH-IPS (Response Time = Normal)

34" 5ms G2G LG.Display AH-IPS (Response Time = Middle)

We can also compare the U3415W with the other 34" ultra-wide display we've tested, the LG 34UM95. The LG was marginally faster than the Dell in our measurements, but in practice it was hard to separate the two to be honest.

34" 8ms G2G LG.Display AH-IPS (Response Time = Normal)

27" 4ms G2G AU Optronics AHVA (IPS-type) @ 144Hz (OD = Normal)

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

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 Acer Predator XB270HU which is a 144Hz refresh rate IPS-type (AHVA) screen. It showed very fast pixel response times, improved in fact as you increase the refresh rate setting. There was no overshoot detected at all as long as you stick with the optimum 'normal' OD setting. The display also features other advanced gaming functions like NVIDIA's G-sync, and Ultra Low Motion Blur (ULMB) mode which really helps reduce perceived motion blur in practice.

There is also a comparison with the excellent 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. There was some slight overshoot noticeable on the Asus but nothing major. This model also features NVIDIA G-sync and ULMB support.

Lastly there is the MVA based Eizo Foris 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 U3415W was decent enough. The two response time settings allow you to choose the best option for your needs. The 'normal' mode was our preferred option, giving a moderate IPS response time of 10.6ms G2G, without introducing any real overshoot. Not quite as fast as we had hoped compared with some of Dell's smaller IPS UltraSharp models. 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 60Hz screen with reasonable IPS gaming performance, it's fine. The curved format of the display provided a slight boost in immersion we felt in gaming, helping to make it feel like the screen is wrapped around your field of view a little. This could be a nice option for immersive simulator type games in practicular.
 

Additional Gaming Features

Aspect Ratio Control - The U3415W has 4 options for aspect ratio control through the OSD 'Display' menu as shown above. There are options for wide 21:9, 16:9, auto resize and 1:1 pixel mapping. Nice to see an auto aspect ratio option available which will maintain the source input aspect ratio and scale to fill as much of the screen as possible. Also great to see a 1:1 pixel mapping mode. Those options would have been handy on other recent UltraSharp models like the U2415 which is a native 16:10 format and lacking the ability to handle a 16:9 source ratio properly.

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.

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 25.6 ms as measured with SMTT 2. Taking into account half the average G2G response time at 5.8ms ('Normal' Response Time setting), we can estimate that there is ~19.8 ms of signal processing lag on this screen, just over 2 frame of delay. This is a moderate lag, and might make the screen a little limited when it comes to very fast gaming and FPS.

 

Movies and Video

The following summarises the screens performance in video applications:

• 34" screen size makes it a good option for an all-in-one multimedia screen, and pushing towards the diagonal size of a lot of smaller end LCD TV's even.

• 21:9 aspect ratio is well suited to videos and particularly movies, leaving smaller borders on DVD's and wide screen content at the top and bottom. The ultra-wide aspect and size is well-suited to watching movies and really works well.

• 3440 x 1440 resolution can support full 1080 HD resolution content.

• Digital interface 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.

• Cables provided in the box for HDMI and DisplayPort.

• 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 ~300 cd/m² and a very good minimum luminance of 16 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 at >1000:1. 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 1089:1 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 noticeably cooler than out calibrated custom mode. It gives you access to the dynamic contrast ratio option as well if you want to use it.

• Good pixel responsiveness which can handle fast moving scenes in movies without issue. No real overshoot issues which is good news. Just stick to the 'Normal' Response Time setting for optimum performance.

• 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 IPS glow from an angle may be an issue for some darker content.

• Some slight areas of backlight leakage but nothing major on our sample which is good. Some uniformity variations may be visible on darker movie scenes in darkened room conditions.

• Good range range of ergonomic adjustments available from the stand, making it easy to position the screen in different ways for viewing from different positions.

• Integrated 2x 9W stereo speakers offered on this model, may be ok for the odd video clip but probably not for any movie viewing.

• Decent enough range of hardware aspect ratio options available which is very useful for external devices.

• Picture By Picture (PbP) and Picture In Picture (PiP) are available on this model.
  
   

Conclusion

The size and format of the Dell U3415W took a few days to get used to, but after that we really did enjoy working with the wide desktop space, high resolution and comfortable pixel pitch size. The curved format was also nice to work with we felt, providing an immersive experience and a more natural feel than the flat 34" models we've seen. Performance wise the factory calibration was very pleasing, with a decent setup out of the box. This was coupled with a strong IPS contrast ratio as well which impressed us. The use of a flicker free backlight and light AG coating, as we've seen from all recent Dell UltraSharp models, was great news as well. Something which Dell should really start promoting we think.

Unlike the LG 34UM95 we tested, the stand was far more versatile here, offering a good range of adjustments. Connectivity was good and it was nice to see a few extras such as the dual USB upstream, integrated speakers and USB 3.0 support offered here. Dell have done a good job with the features on this model. They've even included a high end feature from their premium grade screens, the uniformity compensation function. This worked very well at improving the panel uniformity, it's just a shame it's not more flexible in its operation - being locked at a certain brightness level when used. Response times were moderate for an IPS panel, but we had perhaps hoped for a little better given some of the smaller IPS models we've tested from Dell recently. Maybe the 'fast' response time mode could have done with being a little less aggressive to make it more useable.

Overall the U3415W offered some good all-round performance you'd expect from a modern IPS panel. It was coupled with a nice set of extras, stand adjustments and features making it a nice choice if you are after an ultra-wide screen in this size range.

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Dell U3415W Now Available