Introduction

There's been a real surge in popularity of the ultra-wide market for desktop monitors, with a decent range of screens now available to suit most needs. There's more general all-round displays from the likes of Dell and LG, with flat and curved models available. Then there's some more specialist, gamer-orientated displays around like the Acer Predator X34 and Asus ROG Swift PG348Q for instance, offering high end gaming features like G-sync and overclocked 100Hz refresh rates. What has attracted many people to this sector is the large screen size and high resolution of most models, with 3440 x 1440 being the preferred option above a hand full of 2560 x 1080 screens also available. The ultra-wide format with a 21:9 aspect ratio is an interesting format for split screen multi-tasking, as well as immersive wide screen gaming and models primarily in the 34" bracket have really taken off.

As we discussed recently in our High Refresh Rate Panels and Displays article, there are currently very few real options in the IPS technology space if you want a high refresh rate. AU Optronics were first to venture in to this market with their widely used 27" 2560 x 1440 @ 144Hz IPS-type panel which has become very popular and worked very well. We've already mentioned the hand full of overclocked 34" 3440 x 1440 @ 100Hz models available, making the most of the available 34" panels from LG.Display which are actually natively 60Hz. We've been waiting for LG.Display to get their act together and start producing a native high refresh rate IPS panel of their own, and they've now finally done that with their new 34" panel - first seen in the LG 34UC79G display which we have with us for review. This is a 34" model offering a 144Hz native IPS panel. The resolution is limited to 2560 x 1080 as a result, since current DisplayPort connectivity won't support a higher bandwidth to enable 3440 x 1440 resolution at such high refresh rates. Not to mention there aren't any available panels yet with those specs. This is LG.Display's first venture in to true high refresh rate IPS so it will be very interesting to see how they've handled it, and primarily whether the response times can live up to the requirements of the refresh rate.

The LG 34UC79G display also offers a fair few other interesting gaming features including FreeSync support (50 - 144Hz range) and a Blur Reduction backlight system. We will of course test all these features throughout this review.

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Specifications and Features

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

The 34UC79G offers a pretty good range of connectivity options with DisplayPort 1.2a and 2x HDMI 2.0 connections offered. DisplayPort is needed to support refresh rate up to 144Hz, including FreeSync support from compatible AMD graphics cards (50 - 144Hz range). The digital interfaces are HDCP certified for encrypted content and the video cables are provided in the box for DisplayPort and HDMI.

The screen has an external power supply and comes packaged with the power cable and power brick you need. There are also 2x USB 3.0 ports located on the back of the screen with the video connections with one have charging capabilities as well. An audio headphone jack is also provided in case you want to take sound transmitted to the screen over the video connection, but there are no integrated speakers on this model.

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

OSD Menu

Above: OSD control joystick on the bottom edge of the screen in the middle Click for larger version

The OSD menu is controlled through a single joystick control located on the bottom edge of the screen in the middle. It is a pressable button as well which glows white during normal operation, and flashes on/off white when the screen is in standby.

Pressing the joystick up or down (i.e. away from you or towards you) pops up a confirmation of your current input connection, as well as the active preset mode and whether you have the Smart Energy Saving feature turned on or not. You can't actually change anything though from this pop-up menu oddly. Pressing the joystick left or right allows you to adjust the volume control although since there are no integrated speakers, this is only useful if you're sending sound to the screen and then outputting it via the audio connections to headphones or external speakers. You have to press the joystick button in to bring up any other menus. First you get the above quick access menu which sadly you aren't able to customise to options you'd prefer to have access to. You can quickly switch between inputs here and also enter the 'game' menu with various useful options if you want. You can also enter the main menu by pressing right on the joystick from this quick access first menu.

The 'game' menu looks like the above. You can have quick access to the game preset mode, black stabilizer, FreeSync on/off, blur reduction backlight and response time settings. Useful to have access to all of these quickly and in one place actually give this is a gaming screen.

Above: full top to bottom view of the OSD menu. Click for larger version

When you enter the main menu, a large OSD is shown on the right hand side of the screen, spanning from top to bottom. It's a big menu in size as you can see from the image above. The menu itself is split in to 4 sections down the left hand side. You can navigate quite easily using the joystick, although you do sometimes have to drill through several levels to get where you want. Once closed, the menu won't remember where you last were either, so you have to start navigation again. The options available in each of the 4 sections are shown on the right hand side. The first 'quick settings' menu has options to control the brightness, contrast and volume.

The input menu allows you to switch between the video inputs as well as control the hardware aspect ratio settings.

The 'picture' menu has most of the other settings in it. You can adjust the preset mode via the 'picture mode' option. The 'picture adjust' section allows you to change brightness, contrast, sharpness and turn the dynamic contrast ratio on if you want.

The 'color adjust' section allows you to change the gamma setting, colour temp and adjust the RGB channels.

The 'game adjust' section allows you to alter the response time setting, turn FreeSync on/off and also has the Blur Reduction mode available. We will test all of these functions later in the review.

The 'general' section of the menu is pretty self explanatory as shown above.

All in all there were a decent range of options available in the menu and a good control over most things. Some of the navigation got a bit tiresome through many levels of menu to get to where you want. Navigation was pretty intuitive thanks to the joystick though, but the software felt a little big and chunky in the way it was presented.

 

Power Consumption

In terms of power consumption the manufacturer lists typical 'on' usage of 52W and 1.2W in standby. 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 55.8W at the default 100% brightness setting. Once calibrated the screen reached 33.2W consumption, and in standby it used only 0.5W. We have plotted these results below compared with other screens we have tested. The consumption is comparable to the other large ultra-wide screens we have tested as you might expect, with some of the smaller screens drawing less power (comparing the calibrated states).

Panel and Backlighting

Panel Part and Colour Depth

The LG 34UC79G features an LG.Display LM340WW2-SSA1 AH-IPS technology panel which is capable of producing 16.7 million colours. This is achieved through an 8-bit colour depth. The panel part is confirmed when dismantling the screen as shown below:

Screen Coating

The screen coating 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. Thankfully it isn't a heavily grainy coating like some old IPS panels feature and is also lighter than modern TN Film panel coating. 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.

Backlight Type and Colour Gamut

The screen uses a White-LED (W-LED) backlight unit which is standard 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. LG quote the corresponding 72% NTSC coverage in their spec. 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 (and similar) 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 as advertised, which is great news.

 

Contrast Stability and Brightness

We conducted these tests in the default 'custom' picture adjust preset mode. The brightness control gave us a reasonably good range of adjustment. At the top end the maximum luminance reached 267 cd/m² which was a little higher than the specified maximum brightness of 250 cd/m² from the manufacturer. There was a reasonable 171 cd/m² adjustment range in total, and so at the minimum setting you could reach down to a modest low luminance of 96 cd/m². This might be adequate for those wanting to work in darkened room conditions with low ambient light although we would have liked to have seen a lower possible minimum. A setting of 13 in the OSD menu should return you a luminance of around 120 cd/m² at default settings in this 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 a linear relationship as you can see.

The average contrast ratio of the screen was excellent for an IPS panel at 1251:1. This was fairly stable across the brightness adjustment range as shown above.

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 our new X-rite i1 Pro 2 Spectrophotometer 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 2 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 34UC79G is factory calibrated according to a 'quality assurance report' provided in the box. While this report tells you that it has been calibrated to 2.2 gamma, 6500k white point (within 500k deviance) and dE < 5, it is a little unclear which mode it is referring to. We can only assume it is calibrated in the default setup of the screen which would be the 'custom' picture adjust mode. The report provided with our test sample is shown below for reference:

Default settings of the screen were as follows:

LG 34UC79G - Default Settings

   

 

Initially out of the box the screen was set in the default custom preset mode. With the maximum 100% brightness setting out of the box the screen was overly bright and uncomfortable to use, so you will definitely need to turn that down. You could tell the screen was using a standard gamut backlight as well with the naked eye, and the colour balance and temperature felt pretty good, although a little too warm.

 

We went ahead and measured the default state with the i1 Pro 2. The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) is fairly equal to the sRGB colour space. There is some modest over-coverage in greens and blues but not by anything too significant. Default gamma was recorded at 2.2 average, leaving it with a minor 2% deviance from the target which was great news. White point was measured at a reasonably accurate 6092k, being 6% out from the 6500k we'd ideally want for desktop use and a little too warm. We tested the other colour temperature modes with warm = 6140k, medium = 7801k and cool = 8453k.

 

Luminance was recorded at a bright 275 cd/m² which is too high for prolonged general use. The screen was set at a default 100% 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 0.22 cd/m² at this default brightness setting, giving us an excellent (for an IPS-type panel) static contrast ratio of 1271:1. Colour accuracy was pretty good out of the box with an average dE of 2.7. Testing the screen with colour gradients showed smooth transitions in all shades, with only some slight gradation evident in darker tones. Overall this default setup was reasonably good. Some minor OSD corrections to the RGB channels and brightness should bring the white point closer to 6500k and that will probably be sufficient for most typical users. Not a bad factory calibration overall.

 

 

Calibration

 

We used the X-rite i1 Pro 2 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.

 

LG 34UC79G - Calibrated Settings

   

 

We stuck to the 'custom' preset mode which offered us access to the RGB controls from within the menu. We adjusted the RGB channels and brightness setting as shown in the table above. All these OSD changes allowed us to obtain an optimal 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 with a 0% deviance, correcting the minor 2% deviance we'd seen out of the box. The white point had now been corrected to 6513k, which corrected the 6% deviance we'd seen 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. This left us a black depth of 0.09 cd/m² and maintained an excellent static contrast ratio (for an IPS-type panel) of 1271:1. Colour accuracy of the resulting profile was excellent, with dE average of 0.3 and maximum of 1.1. LaCie would consider colour fidelity to be very good overall. Testing the screen with various colour gradients showed 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. 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. 

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Calibration Performance Comparisons

he 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 pretty good thanks to the factory calibration. You have a reliable gamma curve with 2.2 average and a minor 2% deviance, along with a strong static contrast ratio (for an IPS panel) and pretty low dE. The white point is a little off, and the screen is of course far too bright but some basic OSD adjustments should bring those in line better and be suitable for most users. Some of the other ultra-wide screens we've tested have been pretty good out of the box too and quite comparable to the 34UC79G. The Acer Predator X34 and Asus ROG Swift PG348Q for instance were fairly similar to the LG overall.

The display was very strong when it came to calibrated contrast ratio for an IPS-type panel. At 1271:1 it was actually the highest static contrast ratio we've measured from an IPS-type panel so far, edging out our previous champion the Dell U2417HJ (1228:1 - not shown). Of course none of these IPS panels can compete with VA panel types which can reach over 2000:1 easily, and commonly up to 3000:1 (e.g. Acer Predator Z35).

 

Viewing Angles

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

Viewing angles of the screen were very good as you would expect from an IPS-type 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.

Above: View of an all black screen from the side. Click for larger version

On a black image there is a characteristic glow introduced to the image when viewed from a wide angle, commonly referred to as IPS glow. This type of glow is common on most modern IPS-type panels and can be distracting to some users. Here on the 34UC79G it was a pale blue colour as opposed to the common white glow you see from a lot of IPS panels so was a little less noticeable. If you view dark content from a normal head-on viewing position, you can 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 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 was across the screen, as well as identify any leakage from the backlight in dark lighting conditions. Measurements of the luminance 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. 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 fairly good overall. There was a drop in luminance towards the sides of the screen, more so on the left, where in the worst case the luminance dropped to 98 cd/m² (-22%). That was the most extreme example though and in fact 75% of the screen was within a 10% deviance from the centrally calibrated point which was not bad.

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version

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 no real backlight bleed evident, but a little clouding from the top edge of the screen. Note that this picture was taken from a suitable distance to eliminate capturing viewing angle related IPS glow, which as we've said already may become a problem for some users on a screen this size.

Note: if you want to test your own screen for backlight bleed and uniformity problems at any point you need to ensure you have suitable testing conditions. Set the monitor to a sensible day to day brightness level, preferably as close to 120 cd/m² as you can get it (our tests are once the screen is calibrated to this luminance). Don't just take a photo at the default brightness which is almost always far too high and not a realistic usage condition. You need to take the photo from about 1.5 - 2m back to avoid capturing viewing angle characteristics, especially on IPS-type panels where off-angle glow can come in to play easily. Photos should be taken in a darkened room at a shutter speed which captures what you see reliably and doesn't over-expose the image. A shutter speed of 1/8 second will probably be suitable for this.

 

General and Office Applications

One of the key selling points of some ultra-wide screens is the high resolution and large screen size. A similarly sized 34" display with 3440 x 1440 resolution offers a sharp but comfortable picture and provides an efficient environment for using Microsoft Office programs and internet browsing. This model is a little different as the resolution is more limited at 2560 x 1080. This is a requirement to allow the high 144Hz refresh rate as current DisplayPort 1.2 interfaces will not support 3440 x 1440 @ 144Hz. It's also a limitation of the panel produced, as currently LG.Display only manufacturer this high refresh rate IPS panel in 2560 x 1080 res. They do have a 3440 x 1440 version planned but not until late 2017. So for now, you will need to make do with the more limited resolution here. The 0.312mm pixel pitch is quite large and so text and fonts look quite big. Certainly coming from a 2560 x 1440 27" model that we tend to use day to day, the fonts look big and a bit chunky. Although you soon get used to it and it's not too bad. It might actually be preferable to some people depending on their eye sight and viewing distance. The ultra-wide format does mean you can still comfortable do split screen working, as the 2560 horizontal resolution is sufficient for two side by side windows. We continue to enjoy the curved format of these displays for day to day office work. It just felt more comfortable than a flat screen on a model as wide as this, bringing the corners a little 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 panel is welcome, and much better than the grainy and 'dirty' appearance of older IPS AG coatings. The wide viewing angles provided by this panel technology on both horizontal and vertical planes, helps minimize on-screen colour shift when viewed from different angles, making colour work and photo viewing very viable. The default factory setup of the screen was very good as well, offering an accurate gamma curve, excellent contrast ratio and low dE. A few tweaks in the OSD menu should bring the white point and brightness in line and provide a reliable setup suitable for probably most users, without the need for calibration equipment.

The brightness range of the screen was also very good, with the ability to offer a luminance between 267 and 96 cd/m². This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms although we would have perhaps liked a slightly lower minimum. A setting of ~13 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 are a few extras provided here as well including a 2x port USB 3.0 hub on the back, one with charging support as well from one of them. There is an audio output for headphone connection if you want, although there are no integrated speakers. There were no further extras such as ambient light sensors or card readers on this model which can be useful in office environments. There was a reasonable range of ergonomic adjustments available from the stand allowing you to obtain a comfortable position for a wide variety of angles of tilt, and a decent height adjustment range. Side to side swivel was sadly missing though. The VESA mounting support may also be useful to some people as well.

 

 
Responsiveness and Gaming

The 34UC79G is rated by LG as having a 5ms G2G response time which indicate the panel uses overdrive / response time compensation (RTC) technology to boost pixel transitions across grey to grey changes. The part being used is the LG.Display LM340WW2-SSA1 AH-IPS panel. Have a read about response time in our specs section if you need additional information about this measurement. As a reminder, this is the first native high refresh rate IPS panel from LG.Display, offering a 144Hz maximum.

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 (Overdrive)

The 'response time' setting is available via the picture > game adjust section of the OSD menu as shown above, or also via the quick access 'game' menu. We will test all four modes to see which is optimal first of all. Note that these results were the same from an NVIDIA and AMD test system. For now we have taken these measurements at 60Hz refresh rate, but we will look at the implications of the refresh rate in a moment once we've established the behaviour of the response times under this setting.

In the 'off' setting the response times were slow as you might expect from an IPS panel without overdrive. There was an average G2G response time of 15.6ms measured, but some transitions ranged up to 24.5ms. There was no overshoot since the overdrive impulse was turned off. When you turn the response time setting up a notch to 'slow' there is an improvement, where an average 11.6ms G2G was measured now. Again, a change to 'normal' makes a further small  improvement over the 'slow' mode, down to 9.7ms G2G average and some low levels of overshoot were starting to creep in. Boosting the response times up to the maximum 'fast' mode gives you only a further improvement down to 6.7ms G2G average. At that setting you start to get some some very high overshoot though, particularly with changes from dark to light shades. A reminder, these tests were done at 60Hz and we need to look at the impact of the refresh rate in a moment as this doesn't tell the whole story on its own.

 

Refresh Rate and FreeSync

The 34UC79G supports a refresh rate of up to 144Hz natively, and as we've discussed earlier this is the first high refresh rate IPS panel form LG.Display. When enabled, and from a compatible system, FreeSync is also available which operates in a range between 50 and 144Hz.

From both an AMD and NVIDIA test system we found stable performance without any frames being dropped at all refresh rates from 60Hz to 144Hz which was good news.

Impact of Refresh Rate

Overdrive Mode = Fast

The following tests were completed once the screen had been flashed to the new V2 firmware. We switched to the 'fast' response time setting for now and we wanted to test the response times at a range of refresh rates to see if that influences the pixel transitions. It's quite common for the overdrive impulse to be dynamically controlled across a wide refresh rate range like this. The overshoot can also be impacted we have seen in the past.

As you can see from these measurements the actual pixel transition times do not seem to really change that much overall as you change the refresh rate. We measured basically the same average response time of around 6.8ms G2G across each refresh rate from 60 to 144Hz, while sticking with the same 'fast' overdrive setting in the menu. What did change though was the levels of overshoot, which improved as you increased the refresh rate. So at 60Hz in the 'fast' mode, there were high levels of overshoot detected on a wide range of transitions, but as you reached 120Hz and 144Hz most of the overshoot was eliminated. This is good news of course, but you need to be achieving a high refresh rate really to be able to experience the screen without the overshoot becoming an issue in this 'fast' mode.

As the refresh rate drops below 120Hz the overshoot starts to become far more apparent, and dark and pale halos become more noticeable. Even more so because of the reduced frame rate in fact. Thankfully, unlike the V1 firmware which the screen came with, the response times were at least adequate to support the high refresh rate and frame rate on the most part. By the time you reach the maximum 144Hz too many transitions are slower than the required 6.94ms and you do get some additional smearing introduced in practice. Up to around 120Hz is mostly fine though and probably the upper limit of refresh rate you'd want to push this panel to we think. Again, if you're using this 'fast' mode you don't want refresh rate to be too low either as the overshoot starts to become a problem. We'd say stick to the 'fast' mode for 100 - 144Hz range but preferably try and cap your refresh rate to around 120Hz maximum to avoid additional smearing at the very top end. Whether you'd be consistently able to achieve 144Hz anyway from your system at 2560 x 1080 resolution is probably another consideration.

The panel manufacturer LG.Display will have to do some additional work to their high refresh rate IPS panels to ensure the response times are adequate at the top end, although the ability to support up to around 120Hz quite well is still a big step up from their previous 60Hz panel limit. It was a bit of a shame the panel couldn't really operate at the maximum advertised 144Hz refresh rate without additional smearing and blurring being a distraction.
 

Overdrive Mode = Normal

If you're using the screen at 60Hz - 100Hz then we would recommend sticking with the 'normal' response time setting, as the 'fast' mode has too much overshoot really. This will apply if you're connecting a games console or Blu-ray player for instance where you are limited to 60Hz. That 'normal' overdrive mode resulted in very little overshoot at all refresh rates so is a better option to use when you're operating at these lower refresh rates. By the time you reach towards 100Hz the response times aren't quite fast enough to be keeping up with the frame rate so you get some additional smearing, but at lower refresh rates the response times are fast enough to cope. At 60Hz for instance the average 9.7ms G2G response time was not bad. A little slower than the best 60Hz IPS examples which can reach down to about 8.5ms G2G (with no overshoot). At 9.7ms G2G it was a decent enough IPS offering for 60Hz refresh rate scenarios.

For PC gaming there's a choice to be made with the overdrive control depending on your achievable refresh rate. This will depend on your game, settings, graphics card etc and will also need to be considered if you're using FreeSync to dynamically control your refresh rate. If you're consistently achieving refresh rates in the upper end of 100 - 144Hz then use the 'fast' overdrive mode. If you're operating more in the lower end of 50 - 100Hz, the 'normal' mode is probably best to avoid a large amount of overshoot.

Detailed Response Time Measurements

Refresh Rate = 120Hz, Overdrive = Fast

We stuck with what we consider to be the optimal 'fast' response time setting and 120Hz refresh rate. We know from the previous section of the review that pushing the refresh rate up to the maximum 144Hz returned some additional smearing and blurring as the response times were not quite fast enough to keep up with the frame rate. So this 120Hz refresh rate delivered the upper limit we felt for frame rate. With overdrive set to 'fast', we optimised the response times and made 120Hz frame rates useable, and thankfully at this high refresh rate the overshoot was also kept pretty low.

The average G2G response time was measured at 8.4ms which was a little slow on average for a high refresh rate panel, where really you need to be consistently delivering <8.33ms to keep up with the 120Hz refresh rate. A lot of the transitions were faster than this though and only a hand full dropped below the threshold. So overall, in practice you didn't really get too much additional smearing added to moving content. You will see additional smearing though if you push the refresh rate up to 144Hz as the panel cannot keep up then. Rise times (changes from dark to light shades) were a bit faster on average than fall times (changes from light to dark shades). The lowest response time measured was 4.0ms, reaching below the advertised 5ms G2G figure in fact.

If we evaluate the Response Time Compensation (RTC) overshoot then the results are pretty good at this high 120Hz refresh rate. There were a few transitions where a high overshoot was seen, mostly changes from black to light grey shades. Overall though there wasn't much noticeable overshoot here. As a reminder, this was with the refresh rate at 120Hz and overdrive mode set to 'fast'. We know from our previous tests that in this fast mode, the overshoot becomes more noticeable as the refresh rate drops. You'd probably only want to stick with the 'fast' overdrive mode for 100Hz+ refresh rates. Below that, you'd be better switching to the 'normal' mode we think.

 

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.

As a reminder, these figures are at 120Hz refresh rate and with overdrive set to 'fast'. The response time performance of the LG 34UC79G was not bad overall although the average G2G figure was dragged down a bit by some slower transitions. Still, an 8.4ms average G2G response time was measured with only a few transitions showing overshoot problems at this high refresh rate.

AU Optronics' rival high refresh rate 144Hz IPS-type panels used in models like the Asus ROG Swift PG279Q and Acer XB270HU can reach lower response times of around 5ms G2G though and with no overshoot, and it seems AUO have done a better job maximising their high refresh rate IPS technology. The native 60Hz LG.Display IPS panels which are overclocked to 100Hz used in the Acer Predator X34 and Asus ROG Swift PG348Q also perform a little better, with slightly faster response times of 7.8 - 7.9ms G2G and freedom from any real overshoot problems. It is a little disappointing that the 60Hz IPS panels from several years ago can be overclocked quite nicely to 100Hz and deliver better response time performance than this new native 144Hz IPS panel from LG.Display. Although you do need to keep in mind those 100Hz IPS models are NVIDIA G-sync screens and FreeSync options are only available up to 75Hz maximum using those same panels. So here, with the 34UC79G you have an IPS panel which works with AMD FreeSync and can reliably run up to around 120Hz so that's still a positive thing.

 

1ms Motion Blur Reduction Mode

This is a new feature LG are advertising on some of their screens now, the so-called "1ms Motion Blur Reduction" mode. We already tested this recently on the LG 38UC99, confirming that it is in fact an added strobed backlight feature, designed to help reduce perceived motion blur in practice. Our in depth article about Blur Reduction Backlights talks more about these methods and how they help reduce motion blur for the user, so it's well worth having a read of that if this principle is new to you. This strobed backlight on the 34UC79G (and also the 38UC99) is not linked specifically to AMD FreeSync (like ULMB is linked to NVIDIA G-sync) and we're pleased to confirm you can use this feature from NVIDIA cards as well as AMD.

The 1ms Motion Blur Reduction setting is available in the OSD menu in the 'game adjust' section, and is only available when you've set the screen to a compatible refresh rate in Windows. It is available when set at 60, 100, 120 and 144Hz, but greyed out at 75Hz. If you enable it with FreeSync active, it also turns off the FreeSync setting in the OSD menu, so as expected it is not possible to use both at the same time. Actually, that is a little annoying, as when you want to turn Blur Reduction off, you also have to re-enable FreeSync if you were using it although on the 34UC79G there is a quick access option to get to the game settings from the OSD menu controller.

Blur Reduction Mode Strobing at 144Hz, scale = 5ms
Each strobe lasts 6.94ms (144/second)


Blur Reduction Mode Strobing at 120Hz, scale = 5ms
Each strobe lasts 8.33ms (120/second)


Blur Reduction Mode Strobing at 100Hz, scale = 5ms
Each strobe lasts 10ms (100/second)

Once enabled, we can test the strobing via our oscilloscope as shown above. The strobing cycles the backlight completely off and on in sync with the refresh rate of the screen. We've included the oscillographs here at 144, 120 and 100Hz first of all. Each strobe lasts 1 frame, so at 144Hz it strobes every 6.94ms, at 120Hz every 8.33ms and at 100Hz every 10ms. So that's 144/120/100 times per second. Thankfully at these high frequencies it is hard to spot any visible flicker from the strobing, and the higher the refresh rate the better in that regard. We had found the 75Hz strobing on the LG 38UC99 to be a little too slow and produced some visible flicker, but here it was not a problem as you can run the feature at 100Hz+.

Blur Reduction Mode Strobing at 60Hz, scale = 5ms
Each strobe lasts 8.33ms (120/second)

We've saved the results for the 60Hz strobing to talk about separately as it's a bit different. Manufacturers have two options at low refresh rates. 1 strobe per frame is the typical setup you might expect, but at 60 and 75Hz that produces noticeable flicker which is likely to be problematic to many users. The other option which can be used by manufacturers is to use a "double strobe" system, where the strobing is done twice per frame. In this scenario at 60Hz that would in theory result in 120 strobes per second. That is what LG have used here when using the strobed backlight at 60Hz refresh rate. That might seem a better option as it would certainly be less harmful on the eyes and the visible flicker would be significantly reduced or eliminated for some users. However, double strobing isn't a great system we have seen in the past as it tends to lead to double images and ghosting issues on moving content. There is no option to revert to a a single strobe system. We will look at the blur reduction results in a moment at 60Hz and above.

Enabling the Blur Reduction backlight has a usual impact on the luminance of the display. Thankfully you can still alter the brightness setting in the OSD menu although it should be noted that there are no other controls or options to adjust the strobe timing or strobe length or anything like that. A consideration for users of these blur reduction backlights is the maximum brightness you can still achieve with the feature enabled. Here, it is a reasonably good 141 cd/m² which should allow the feature to be used for gaming where brightness needs to be at a similar level to normal every day use. Unfortunately, the menu does not remember a brightness setting for Blur Reduction on and off modes, so you have to manually change the brightness slider when you enable Blur Reduction, and then when you turn it back off (unless you just stick with the same brightness setting of course). A typical every day brightness of around 14% would be comfortable for normal desktop use, but when you enable blur reduction the resulting ~70 cd/m² may be too dark for gaming.

Note: Pulse Width setting at max where applicable.
*Note 2: The Acer XB270HU was later updated to include a 120Hz mode, which will produce a slightly darker maximum luminance

If we compare the max luminance of all the screens we've tested with a blur reduction strobed backlight we can see that the LG 34UC79G offers a slightly brighter display than many of the other options, which is a good thing. If you need a slight improvement in brightness, you can also use the feature at a lower refresh rate, where the less frequent strobes result in a slightly brighter image.

Blur Reduction Tests

 

Of course the main thing we want to test is what improvements the Blur Reduction mode offers when it comes to motion clarity and gaming. We were pleased with the results we'd seen from LightBoost backlights when we tested them, and also from the natively supported blur reduction feature on other displays including the popular gaming models we've tested as listed above.

 

We used the BlurBusters full-screen TestUFO online motion test to help establish the image clarity at different areas of the screen. These tests were conducted at 120Hz refresh rate and with overdrive set to 'fast'. The results are represented by the image below which gives you a sample from 5 areas of the screen, from top to bottom using a pursuit camera setup. That gives you a real-life indication of the perceived motion clarity on the screen using the Blur Reduction feature. We didn't find the blur reduction feature on the 34UC79G very good though to be honest. Tracking of moving objects did become a bit easier and the image looked sharper and clearer. However, there was quite a lot of strobe crosstalk evident which resulted in ghost trails behind the moving tests. This was particularly noticeable in the bottom region of the screen, but even the best areas showed quite high levels of strobe crosstalk. The central region of the screen would normally be the area you'd want the best clarity, but as you can see there's some high levels of ghosting here as well. It looks like the strobe timing needs adjusting by LG really. We have flagged this as a concern to LG in case it can be adjusted as part of the firmware update.

 

 

Pursuit camera photos representing strobe cross talk from top to bottom regions of the screen.

 

Additional Gaming Features

Aspect Ratio Control - the 34UC79G has 5 options for aspect ratio control through the OSD 'Display' menu as shown above. There are options for full wide, original, 1:1 pixel mapping and 2 different 'cinema' modes. The cinema modes are designed for 21:9 full screen viewing, with and without captions. The presence of an 'original' mode to maintain the source aspect (but fill as much of the screen as possible), and 1:1 pixel mapping should be very useful, and certainly welcome given not all content and inputs are this 21:9 native aspect ratio.

Preset Modes - There are several specific game preset modes available from the 'picture mode' menu. There are FPS Game 1, FPS Game 2, RTS Game and Custom (Game) modes to choose from. All have differing preset values, with some settings being locked in certain cases like sharpness and even the response time control. These modes may be useful if you want a slightly different setup for gaming, perhaps with accentuated sharpness and a brighter display which would be fairly typical. You could even have a mode where the Blur Reduction backlight is enabled by default.

Black Stabilizer - You can adjust this slider to change the black saturation levels in dark images, to help bring out detail in darker scenes. Might be useful if you play a lot of darker games. LG's website also talks about the 'Dynamic Action Sync' setting which seems to imply it reduces input lag. Actually there is no setting in the menu at all for this, so we can only assume it's an always active feature.

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 10.0 ms as measured with SMTT 2. Taking into account half the average G2G response time at 4.2ms, we can estimate that there is ~5.8ms of signal processing lag on this screen which is very low and shouldn't represent any problems in gaming.

 

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, but being quite a bit smaller than most modern LCD TV's of course even at this massive size.

• 21:9 aspect ratio is more well suited to videos, more so than the wide range of 16:9 format screens around, leaving smaller borders on DVD's and wide screen content at the top and bottom.

• 2560 x 1080 resolution can support full 1080 HD resolution content

• Digital interfaces support HDCP for any encrypted and protected content

• Good range of connectivity options provided with DisplayPort and 2x HDMI offered.

• Cables provided in the box for DisplayPort and HDMI (x1).

• Light AG coating providing clean and clear images, without the unwanted reflections of a glossy solution.

• Wide brightness range adjustment possible from the display, including a maximum luminance of ~267 cd/m² and a fairly decent minimum luminance of 96 cd/m². This should afford you good control for different lighting conditions. Brightness regulation is controlled without the need for PWM and so is flicker free for all brightness settings.

• Black depth and contrast ratio are excellent for an IPS-type panel at 1271:1 after calibration. Detail in darker scenes should not be lost as a result.

• There is a specific 'cinema' preset mode available for movies or video if you want which doesn't look that dissimilar to our calibrated custom mode, other than the brightness being at 100% and some of the other settings now being greyed out and locked. Might be useful to set up at a specific brightness level for movies though.

• Decent pixel responsiveness which should be able to handle fast moving scenes in movies without issue. Low overshoot issues which is pleasing in the normal mode, which you may want to stick to for movies. The 'cinema' preset mode is locked to this response time mode in fact.

• Wide viewing angles thanks to IPS-type panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles.

• IPS glow is a little less obtrusive since it is a pale blue glow and not the usual white glow, but given the screen size you might experience some annoying glow on darker content from an angle.

• Good and easy to use tilt and height ergonomic adjustments available from the stand, although the lack of a side to side swivel function is a shame for re-positioning the screen for movie viewing from a distance, or with other people.

• No significant backlight leakage, and none from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here.

• No integrated stereo speakers on this model but there is an audio output connection and one for headphones if needed.

• Decent range of hardware aspect ratio options including 'original' aspect ratio retention and a 1:1 pixel mapping mode.

• Picture in picture (PiP) and Picture By Picture (PbP) are not available.
   

Conclusion

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Focusing first of all on gaming, which is the 34UC79G's primary purpose, the screen does mostly pretty well. This is the first high refresh rate IPS panel from LG.Display (the panel manufacturer, not LG the screen manufacturer) and they've done a pretty good job with it. Response times are capable of supporting up to 120Hz refresh rate pretty reliably, which is a significant step up from their previous native 60Hz panels. We were a little disappointed at the very top end as 120 - 144Hz showed too much added smearing where response times couldn't keep up with the frame rate. You do need to be mindful of your overdrive setting, choosing between 'normal' and 'fast' depending on your use and achievable refresh rate. Although that's not too much of an issue and it's easy enough to change. It is worth noting that in the 34" IPS space, the only other high refresh rate options are the overclocked 100Hz models, which are combined with NVIDIA G-sync to allow that to function properly. The 34UC79G is therefore the first high refresh rate IPS offering in this space with FreeSync support so that's quite an attractive feature. Input lag of the screen was nice and low too which was pleasing, and there's a decent range of extra gaming features offered from the screen. We were disappointed with the blur reduction mode which seemed to show too much strobe cross-talk on moving content and was not really worth using.

In other areas the screen offered good all-round performance as you would hope for from an IPS panel. Wide viewing angles and a stable image quality were supported by a decent factory calibration and an excellent static contrast ratio for this panel technology. Light AG coating and a flicker free backlight are always welcome and the design, stand and connectivity were also good on this model. The 2560 x 1080 resolution is more limiting for general day to day office uses than the range of 3440 x 1440 resolution models, but it's a trade off at the moment as it allows for the higher 100Hz+ refresh rate and will also be far less of a drain on your system for high frame rate gaming.
 

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