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Introduction

The growth in gaming monitors over the last couple of years has been significant and we realise a lot of our reviews during that time have been for high end gaming screens, as after all that's where some of the most exciting developments have been happening. We've seen high refresh rate IPS and VA panels emerge, ultra-wide curved screen formats, NVIDIA G-sync and AMD FreeSync technologies and a whole host of other advances in the market. In July 2014 we reviewed the Asus ROG Swift PG278Q gaming display, the first to feature NVIDIA G-sync variable refresh rate technology. Since then, the ROG Swift (Republic of Gamers) brand has been synonymous with monitor gaming excellence and has really helped the Asus gaming range take off. We've seen other impressive gaming screens since then including the ROG Swift PG279Q, the IPS-based follow up to the PG278Q. We've got the latest exciting model from the Asus ROG Swift range with us now for testing, the massive 34" curved ultra-wide PG348Q. This model has been eagerly anticipated since June last year when the prototype was first announced and it's finally being released now by Asus Worldwide. We've had a bit of a taste of what we might expect in the mean time with the launch of Acer's equivalent Predator X34 model which we reviewed in September 2015.

The new ROG Swift PG348Q features a massive 34" ultra-wide screen size, with 3440 x 1440 resolution. The IPS panel can be overclocked up to 100Hz refresh rate from its native 60Hz support and has been paired with NVIDIA G-sync technology for improved gaming performance. A few other gaming extras have been incorporated as well and the screen features a new "ROG Armour Titanium and Plasma Copper colour scheme" design. We will see how it compares to the other successful ROG Swift gaming screens as well as the Acer Predator X34 throughout the course of this review.

If you appreciate the review and enjoy reading and like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you. We worked overtime to bring you this review nice and quickly as we know how excited people were to see how this screen performs.

Specifications and Features

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

The PG348Q offers a limited range of connectivity options given the use of a G-sync module. However, these have improved since the early G-sync capable screens which only featured a single DisplayPort interface. This model offers DP 1.2a and an additional HDMI 1.4 input as well which is useful. The digital interfaces are HDCP certified for encrypted content and the video cables are provided in the box for DisplayPort and HDMI, along with a USB cable.

The screen has an external power supply brick which comes packaged along with the power cable you need. There are also 4x USB 3.0 ports, located on the back of the screen next to the video and power connections. There are also some 2x 2W RMS sound integrated speakers, but no further extras like card readers, ambient light sensors or human motion sensors provided as those are more aimed at office uses, while this is primarily a gaming screen.

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

OSD Menu

   
Above: OSD control buttons on the back right hand side of the screen (when viewed from the front)
Click for larger version

Power Consumption

In terms of power consumption the manufacturer lists 'power on' usage of <100W (a little non-committal!), and 0.5W 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 57.5W at the default 80% brightness setting. Once calibrated the screen reached 36.5W consumption, and in standby it used only 0.5W. We have plotted these results below compared with other screens we have tested. The calibrated consumption is very similar to the Acer Predator X34 (40.6W) but a little more than the Acer XR341CK FreeSync model (30.7W) and Dell U3415W (32.1W):

Panel and Backlighting

Panel Part and Colour Depth

The PG348Q features an LG.Display LM340UW2-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. Especially when this is a gaming screen and you're more likely to have a gaming graphics card than a pro-grade 10-bit capable card connected. 10-bit support requires relevant applications as well, so to many people this 10-bit support might be irrelevant. The panel part is confirmed when dismantling the screen. Incidentally this is the same panel we saw used in the Acer Predator X34 / XR341CK gaming screens and the Dell U3415W display as well.

Screen Coating

The screen coating on the PG348Q is a light anti-glare (AG) offering, the same as that featured on the Acer competing models as well. 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, including popular gaming screens. It retains its anti-glare properties to avoid too many unwanted reflections of a full glossy coating, but does not produce an too grainy or dirty an image that some thicker AG coatings can. There were some very slight cross-hatching patterns visible on the coating if you looked very closely, but nothing very obvious.

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. 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, as advertised.

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 341 cd/m² which was actually a fair bit brighter than the specified maximum brightness of 300 cd/m² from the manufacturer. There was a decent 308 cd/m² adjustment range in total, and so at the minimum setting you could reach down to a very low luminance of 33 cd/m². This should be adequate for those wanting to work in darkened room conditions with low ambient light. A setting of 27 in the OSD menu should return you a luminance of around 120 cd/m² at default settings. It should be noted that the brightness regulation is controlled without the need for Pulse Width Modulation, using a Direct Current (DC) method for all brightness settings between 100 and 0% and so the screen is flicker free as advertised.

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 very good for an IPS-type panel with an average of 1093:1. This was nice and 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

Default settings of the screen were as follows:

Asus ROG Swift PG348Q - Default Settings

  

Initially out of the box the screen was set in the default 'Racing mode' preset. The colour temp setting was on the 'user mode' as well with RGB channels all available but set at 100% each to start with. You could tell the screen was using a standard gamut backlight and the image looked pretty good, but too bright for comfortable use. Colour balance felt good although a little warm, and the image quality was decent. 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, mostly in blue and green shades but not by anything significant. Default gamma was recorded at 2.2 average, leaving it with a 0% deviance from the target which was excellent news, especially since the OSD menu does not offer any gamma adjustment settings. White point was measured at 6107k being slightly too warm from the target of 6500k but with a low 6% deviance. The screen was set in the default 'user mode' colour temp mode incidentally. We again tested the other modes which returned the following colour temperature results:

Colour Temperature Modes

The white point was probably best at the default 'user mode' out of the box, and closest to our target of 6500k. It does also give you access to the RGB channels to calibrate the screen yourself which should allow for fairly simple correction of that colour temperature, as shown in the calibration section that follows. Luminance was recorded at a very bright 296 cd/m² which is too high for prolonged general use. The screen was set at a default 80% 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 a very good static contrast ratio (for an IPS-type panel) of 1120:1. Colour accuracy was also good out of the box with a default dE average of 2.4, and a maximum of 5.7. Testing the screen with colour gradients revealed smooth gradients with some minor gradation evident in darker tones as you see from most screens.

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.

Asus ROG Swift PG348Q  - Calibrated Settings

   

All the OSD changes listed above 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 maintained at the accurate 2.2 average we had seen out of the box and no real adjustment was needed there. The white point had been nicely corrected thanks to the adjustments to the RGB levels. It was measured now at an accurate 6490k (<0.5% deviance). Luminance had been improved thanks to the adjustment to the brightness control and was now being measured at 119 cd/m². This left us a black depth of 0.11 cd/m² and maintained a very good static contrast ratio (for an IPS-type panel) of 1090:1. Colour accuracy of the resulting profile was very good with dE average of 0.5 and maximum of only 1.6. Testing the screen with colour gradients revealed smooth gradients with some minor gradation evident in darker tones as you see from most screens.
 

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 overall, with an accurate gamma curve and low dE. White point was slightly too warm but only by a minor 6% deviance, and contrast ratio was strong for an IPS panel. Some basic OSD adjustments to the RGB channels can correct that white point and you're good to go!

The display was strong when it came to black depth and contrast ratio for an IPS panel. With a calibrated contrast ratio of 1090:1 it was comparable to some of the better screens using this kind of panel technology. It was not quite as high as the 25" Dell U2515H (1138:1 - not shown here) which holds the record for an IPS contrast ratio. It was very similar though to the Acer Predator X34 (1033:1) and Dell U3415W (1091:1) which share the same LG.Display panel. Of course none of these IPS screens can compete with VA panel types which can reach up to around 3000:1 easily like the 35" Acer Predator Z35 (2813:1), and even close to 5000:1 in the case of the 24" Eizo FG2421 (4845:1).

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 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. For a gaming screen, this is one of the big positives of using IPS panel technology as opposed to the common TN Film matrices which are generally adopted in gaming displays.

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

On a black image there is a characteristic pale glow when viewed from an angle, commonly referred to as "IPS-glow". On the PG348Q this actually appeared a little more purple in hue than the competing Acer Predator X34 where it appeared more white. Odd given that it's the exact same panel, but perhaps some variation in the panel coating here. This type of glow 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 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 not great. The top half of the screen was quite a bit darker than the bottom half unfortunately, although in day to day normal use and multimedia you couldn't really spot this. The luminance dropped by -35% down to 89 cd/m² in the most extreme example in the upper left corner. The lower middle area was more uniform and closer to the 120 cd/m² calibrated central point. Only 50% of the screen was within a 10% deviance threshold. Results may vary from sample to sample of course, and as we've said, in gaming and multimedia you don't really notice this variance day to day.

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 a very small amount of backlight bleed detected in the top left corner but it was at a low level. There was no other obvious leakage of clouding of the backlight here which was pleasing.

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 ultra-wide screens like the this 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. It might be orientated at gamers, but it's IPS panel can deliver strong performance in other areas as well making it a good all-rounder. 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 setup of the screen was good and represented a decent setup for most users. Some simple OSD tweaks can bring the white point closer to the target which was really the only issue there. We were also pleased with the strong 1090:1 contrast ratio after calibration as well which was good for an IPS panel.

The brightness range of the screen was also very good, with the ability to offer a luminance between 341 and 33 cd/m². This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms. A setting of ~27 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 whistling noise from the screen if you listened very closely, even when using the full overclocked 100Hz refresh rate. There is talk online about "coil whine" from screens when they are overclocked in some cases, but we saw - or rather heard - no evidence of that here on our test system during any normal day to day use over the few weeks of testing the screen. We found we could introduce some coil whine at 95 and 100Hz using specific test patterns but as we said earlier, it's questionable whether you'd ever experience this in normal uses. The screen also remains fairly cool even during prolonged use. There is no specific preset mode for office work or reading so you will have to set one of the other modes how you want. With 6 preset modes available to change and save, you can easily set others up if you need for different gaming situations. Even with the use of G-sync v II, the screen is limited when it comes to connectivity options with only DP and HDMI available. Picture in Picture and Picture by Picture options are not provided on this model as a result of the G-sync module and the inability to add a scaler to the screen as a result.

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. They are all located on the back of the display so are not easy-access really. Integrated 2x 2W RMS speakers can provide sound for the odd YouTube clip or mp3 if you want. There are no further extras like ambient light sensors or card readers which can be useful in office environments. Remember, this is aimed at gamers really. There was a decent range of ergonomic adjustments available from the stand allowing you to obtain a comfortable position for a wide variety of angles. They were mostly stiff though so you might not want to move it around too often. The VESA mounting support may also be useful to some people as well for more flexibility.

 
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 3440 x 1440 and at a 60Hz native 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 clear. When running at a 1080p resolution the text is still reasonably clear, with moderate levels of blurring. You do lose a lot of screen real-estate as well of course but the image seems to be quite well interpolated if needed. May be handy for some systems where outputting games at 3440 x 1440 @ 100Hz is a challenge.

Gaming Introduction

The new ROG Swift PG348Q ultra-wide screen is clearly gamer-orientated, pairing an ultra-wide format curved display with a few gaming enhancements to deliver an interesting option for gamers. Firstly we should consider the format of the screen, with the 34" area offering a nice immersive experience and the wide 21:9 aspect proving popular for many gamers since it was introduced. It's nice also that the screen offers the full 3440 x 1440 resolution currently available on models this size, as opposed to the more limited 2560 x 1080 some 34" models have. That extra resolution provides a clarity boost for all uses, including gaming. It does add some additional demand on to your system and graphics card of course, but at least there is also G-sync (discussed in a moment) to help with varying frame rate outputs. Or if you really need to you can switch down to 2560 x 1080 anyway, and we've seen the image is quite well interpolated. The slight curve to the screen also adds to immersion feeling in games and we prefer it to flat 34" ultra-wide models certainly.

At the moment the 34" monitor space is a little limited by the panels being manufactured. At the moment only LG.Display and Samsung seem to be investing in this format, with nothing reported in the roadmaps for other main manufacturers like AU Optronics or Innolux. There's really only the choice for display manufacturers between LG.Display's IPS, and Samsung SVA panels. That's not necessarily a bad thing as IPS is always very popular with buyers and using an IPS panel like Asus have here, does allow them to offer a screen suitable for a wide range of uses, not just exclusively for gaming. There are no TN Film panels in this size and format at the moment so the IPS option is about as good as you can get at the moment for gaming needs. Unfortunately, IPS is somewhat limited in what it can offer. This isn't a fault of Asus, they are only working with what panels they have available to them and making the most of them. IPS technology (and Samsung SVA for that matter) is still fairly limited when it comes to pixel response times. It can't compete with the speed of TN Film panels, and as yet LG.Display haven't found a way to drive response times lower like AU Optronics have with their recent high refresh rate AHVA (IPS-type) panels in the 27" space (e.g. the Asus ROG Swift PG279Q). Still, people have been using IPS for many years for gaming so there's no reason to think that a screen like this couldn't be used as long as the response times are handled right. We will look at that in the next section but we've seen positive things already from the Acer equivalents. Sure, they won't be quite as fast as TN Film panels, but they are still fine for many users. The availability of TN Film panels in this format would have given Asus more choice perhaps, and the ability to offer an even better gaming experience. Although we expect people would only then moan about the restrictions of TN Film for other uses.

This leads us on to refresh rate. Again Asus are limited here by what is available panel-wise. LG.Display have yet to release any native high refresh rate (144Hz) IPS panel in any size. They had a 27" 1080p panel expected in Q3 last year but it's not emerged yet and perhaps indicates they are still in development or have perhaps been scrapped in favour of investment elsewhere. Response times are likely to be the limiting factor in their quest, as they need to be able to reliably drive them under 6.94ms average (without loads of overshoot) to make 144Hz viable. That aside, an even bigger problem is that the 3440 x 1440 resolution offered on a screen this size is too high to run at 144Hz with current DisplayPort standards. We would need to see DisplayPort 1.3 for that kind of bandwidth to be viable which isn't expected on graphics cards until later this year. All in all, it's likely to be a fair amount of time before we see a 144Hz native 3440 x 1440 screen sadly. In the mean time, Asus have done what they can with the available panel, within the confines of what it will support from an overclocked refresh rate point of view.

Boosted Refresh Rates

The panel being used here is a native 60Hz panel, but Asus have built in an "overclocking" feature which allows the user to reach up to 100Hz refresh rate maximum. This can be easily enabled via the OSD menu using the 'Over clocking' section. You toggle the option on and then you can select a maximum refresh rate setting from 75 to 100Hz in 5Hz steps. Once you've selected your maximum refresh rate you press enter and the screen reboots. From there, you should be able to go in to Windows or your graphics card settings as normal and change your selected refresh rate up to whatever you choose as the maximum, again in 5Hz steps above 75Hz. The reason for the steps from 75 to 100Hz to accommodate people who perhaps don't have a powerful enough system for the maximum setting and want to cap the upper limit lower. Asus also recommend you are using a G-sync capable card from NVIDIA which would be logical since you're paying a fair chunk of money for the privilege of having G-sync available. Those cards should apparently handle the overclock up to 100Hz although a GTX 980 Ti or above is recommended for optimum performance apparently.

We will test these higher refresh rates during the following sections of this review, checking if any frames are dropped and if there appear to be any side effects. One other note is that the Turbo key on the right hand side of the screen with the menu controls can be used to quickly switch between 60Hz and 100Hz (once you've enabled the overclock) if you want.

This higher refresh rate support has been paired with an NVIDIA G-sync module, offering G-sync variable refresh rate support between 30 and 100Hz. The overclocking facility of the screen seems to be related to the presence of a G-sync module, or perhaps more precisely down to the absence of a built-in scaler. Other overclockable screens we've tested so far like the Asus ROG Swift PG279Q @ 165Hz and Acer Predator Z35 @ 200Hz are also G-sync capable so that seems to be the key here. With G-sync being provided you can run the screen potentially at the maximum 3440 x 1440 @ 100Hz but know that the refresh rate will be dynamically controlled to avoid tearing and stuttering by the G-sync module if needed. G-sync is certainly a very useful feature and very important on high resolution/high refresh rate gaming screens now.

Additional Gaming Features - Where is ULMB?

Sadly one thing which is missing from the PG348Q is a Blur Reduction mode. We were hoping ULMB would be available as part of the G-sync module, and some early press reports and specs suggested it would be featured here but it has not been provided. Presumably that has something to do with the refresh rate range, as providing ULMB at lower refresh rates <85Hz is generally considered too flickery, and since the higher refresh rates are not guaranteed here it was probably too much to ask for. NVIDIA 3D Vision is also not supported, as that needs refresh rates of 120Hz minimum to function correctly (60Hz per eye in active shutter mode).

Responsiveness and Gaming

The ROG Swift PG348Q is rated by Asus as having a 4ms G2G response time, 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 'OD' (overdrive) option. The part being used is the LG.Display AH-IPS LM340UW2-SSA1 panel, the exact same panel as already used in the Acer Predator X34 and Dell U3415W displays. 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 PG348Q comes with a user control for the overdrive impulse available within the OSD menu in the 'image' section. There are 3 options available here under the OD setting. First of all we carried out a fairly small set of measurements in all 3 of the OD settings. These, along with various motion tests allowed us to quickly identify which was the optimum overdrive setting for this screen. Note that for now we have stuck with the native 60Hz refresh rate of the panel. These tests are just designed to help us identify the optimal OD setting, and we will check the response times again when we come to overclock the refresh rate.

Firstly we tested the response times with OD set to off, effectively turning off the overdrive impulse. The average response time was measured at 13.4ms G2G average which was actually not that slow, but certainly not optimum for this technology. Rise times were quite a bit slower than fall times and there was some obvious blurring to moving images. There was no overshoot in this mode since OD was turned off, but we would hope for better responsiveness from the other modes.

Switching up to the 'Normal' OD setting brought about some positive changes to response times. G2G average had reduced down to 10.1ms now which was better, but a little slower than the best case 60Hz IPS panels around, which can reach down to around 8.6ms G2G without introducing noticeable amounts of overshoot. We had perhaps hoped for a little faster here with a slightly more aggressive overdrive impulse perhaps to push response times down nearer that figure. Remember that this small sample set was at 60Hz refresh rate so we may see some improvement when we switch up to the overclocked refresh rates in a moment. There was still no overshoot at all in this mode, suggesting that perhaps the overdrive impulse could be pushed a little further perhaps to boost response times.

Finally we tested the 'Extreme' OD setting. There was an improvement in measured response times down to 7.5ms G2G average but at the cost of some very high overshoot, which was obvious and distracting during actual use. Stick with the 'normal' OD mode for optimal performance.

We can also make some visual comparisons of the three OD settings using the moving images of the PixPerAn tool. The above photos were captured in each of the OD modes. With OD off, there was a fairly obvious blurring to the moving image, something that was largely eliminated when switching up to the 'normal' mode. It wasn't quite as clear as some other IPS panels we've tested, particularly those with high refresh rates but it was certainly a sharper and clearer image than with OD off. There were no signs of overshoot either in this mode which was pleasing. The 'extreme' mode pushed things too far, and dark overshoot trails were introduced as you can see. Stick with the normal mode for optimal performance.

Refresh Rate

One of the most interesting features of the PG348Q is the overclockable refresh rate. The panel itself is designed to run at 60Hz by LG.Display and that's the native refresh rate you will be able to select in Windows when you first connect the screen. However, there is a specific feature available in the OSD menu in the 'over clocking' section as shown above. This allows you to enable the higher refresh rate support. We've already talked about this support in more detail in the gaming introduction section.

We had no issues with selecting and running the screen at any of these refresh rates from our tests system, using an NVIDIA GTX 750 graphics card. All of them worked fine in Windows with no visible artefacts or flickering. Some users have reported some coil whine from other overclockable screens (it's very early days for this particular model) when using overclocked refresh rates but we heard nothing different at any refresh rate. If you do have a really obvious whine from the screen which is an issue for you, we would suggest contacting Asus or the retailer for an RMA as that doesn't seem to be an issue affecting every sample. Certainly ours was fine. From the NVIDIA GTX 750 card we tested the screen using the BlurBusters.com frame skipping test and found that the screen did seem to drop frames at all refresh rates, including the native 60Hz. Perhaps the card is not powerful enough for this screen or isn't fully compatible. Asus recommend a GTX 980 Ti or higher and so we tried one of those as well.

With an NVIDIA GTX 980 card we found no issues with running the screen at any refresh rate between 60 and 100Hz. The image was stable and there was no flicker or coil whine. Thankfully with this card we saw no frame skipping at any refresh rate, all the way up to the maximum 100Hz. Asus recommend a high end NVIDIA card for use with this screen so this is perhaps not surprising, but something to keep in mind. This is very much a high end gaming screen and so we expect a lot of potential users will have very advanced gaming PC's to run it on anyway. You'd need something high end to power 3440 x 1440 @ 100Hz.

We also tried the screen from an AMD Radeon R9 290 series graphics card where we had more trouble. You could select refresh rates all the way up to 100Hz fine, but anything above 60Hz resulted in periodic flickering of the screen. It seems the screen is perhaps more fussy from AMD systems when using the overclocking feature, so stick with a high-end NVIDIA card for this model (which you probably would given it's a G-sync model anyway). We found the competing Acer Predator X34 less fussy when we tested it, which worked fine from our NVIDIA GTX 750 card and the AMD Radeon R9 290 series as well, without any flickering or frames being dropped. It does seem the Asus is more fussy.
 

60Hz Refresh Rate

100Hz Refresh Rate

On another interesting note, we found that the response times were improved when running at a higher refresh rate. We've seen this from some other screens as well where response times are somewhat influenced by the active refresh rate. Here, we saw a decent improvement in response times when you compare them at 60Hz and at 100Hz. In both cases we were using the optimal OD normal setting by the way. Pixel transitions improved down to 7.7ms G2G with the 100Hz refresh rate, and it remained free of any overshoot problems. A pleasing result, and some decent response times from an IPS-type panel. With an average G2G of 7.7ms, it is suitably low enough to support the 100 fps frame rate available here, since the screen needs to refresh every 10ms. When response times are slower than the refresh frequency excess blurring and smearing can be introduced, but that's not a problem here on the PG348Q. The G-sync operating range is 30 - 100Hz maximum, depending on if you've used the overclocking feature which gives you a nice wide range. Given the high resolution here, the G-sync support combined with a wide dynamic range should provide a very pleasing gaming experience. We ran some G-sync tests which looked smooth and performed well.

One thing we did notice on our test systems was an odd behaviour with the overdrive impulse at the maximum 100Hz refresh rate, and also at one step down of 95Hz. If you observe the moving car in the PixPerAn tests you can see this issue. Approximately every 10 seconds the overdrive impulse seemed to "jump", causing a large amount of overshoot to momentarily appear in front of the moving object, before quickly reverting to its normal operation. It was a very quick change but you could see it clearly. At 100Hz and with OD set to normal there is no overshoot trailing at all normally behind the car. When this "jump" happens a noticeable and pretty severe dark and pale overshoot appears in front of the car before reverting back to normal again and going through the same cycle. It was an odd behaviour and we can only assume it was an artefact resulting from the excessive refresh rate boost above the native 60Hz. At overclocked refresh rates between 60 and 90Hz this did not appear, so it seemed to be only when pushing the screen to the limit of its refresh rate overclock. We had seen something similar when we tested the Acer Predator Z35 at its maximum 200Hz overclock setting.

Perhaps this will vary on other systems and graphics cards although we found it did the exact same thing on both NVIDIA GTX 750 and 980 cards and our AMD Radeon system as well. We have fed this back to Asus for testing and comment and will update this part of the review when we have more information.

For now, we would recommend sticking with 90Hz as the maximum overclock speed and refresh rate setting where this overdrive anomaly is not present. You are still getting a 50% boost in refresh rate/frame rates compared with the native 60Hz panel, and some nice additional benefits in terms of improved response times and improved perceived motion blur. Powering the screen at 3440 x 1440 and above 90Hz on a regular basis is probably going to be a challenge in most games anyway, so we don't expect our 90Hz upper cap recommendation to be a problem really.

More Detailed Measurements
OD Normal, 100Hz Refresh Rate

Having established that the OD normal setting offered the best response/overshoot balance we carried out our normal wider range of measurements as shown below. We used the maximum overclocked refresh rate of 100Hz since that had been stable on our test system and delivered the optimal response time performance.

The average G2G response time was more accurately measured at 7.8ms which was very good overall for an IPS-type panel. Transitions were a little slower on rise times (changes from dark to light) but not by anything significant. One transition (0-100) seemed to be a little slower than everything else, measured at 13.5ms, where the overdrive impulse was perhaps not quite as well tuned. Overall the response times were faster than the best 60Hz IPS panels available at the moment, which can reach down to about 8.6ms G2G average without overshoot. Here, the 100Hz overclocked refresh rate helped push them a little lower which was pleasing.

There was no overshoot at all on any transition as long as you were using the maximum refresh rate. Having tested OD normal at 60Hz there was also no overshoot detected there either.
 

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.

When using the screen at the native 60Hz refresh rate the response times (10.1ms G2G) were a bit slower than some of the best 60Hz IPS-type panels available, which can reach down to ~8.6ms G2G while remaining free of overshoot. When you push the refresh rate up to 100Hz the response time are improved nicely, down to 7.8ms G2G which is impressive. There is also no overshoot at all at this refresh rate as long as you stick to the 'normal' OD mode. This left the screen as being basically the same as the Acer Predator X34 (7.9ms) and slightly faster than the FreeSync Acer XR341CK (8.7ms) because that model had a lower maximum 75Hz refresh rate. The ROG Swift PG348Q was also quite a bit faster than the other 34" widescreen displays we've tested like the Dell U3415W (10.6ms G2G) and LG 34UM95 (9.5ms G2G), again thanks to the faster refresh rate. Very pleasing performance really when it comes to pixel response times.

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" 4ms G2G LG.Display AH-IPS @ 100Hz (OD = Normal)

In practice the Asus ROG Swift PG348Q performed best with OD at normal. There were low levels of blurring evident, the image looked sharp and there was no overshoot at all. The support for higher refresh rates up to 100Hz provided additional levels of motion clarity and image smoothness which surpassed what was possible from 60Hz panels. The additional G-sync support for NVIDIA users will also be of real benefit.

34" 4ms G2G LG.Display AH-IPS @ 100Hz (OD = Normal)

34" 4ms G2G LG.Display AH-IPS @ 100Hz (OD = Normal)

34" 4ms G2G LG.Display AH-IPS @ 75Hz (OD = Normal)

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

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

The above images show a comparison first of all with the most direct competitor, the Acer Predator X34. That model performed very similarly which is not surprising since they are both using the same exact panel, and our response time measurements revealed almost identical overall performance. Acer XR341CK model (FreeSync version) along with the other two other 34" ultra-wide screens we've tested are also then shown. The PG348Q with its faster response times and higher refresh rate was a bit better than the Acer XR341CK with a less noticeable blurring. The Dell U3415W featured the exact same panel as the Asus/Acer screens but was a little slower than both in practice we felt. Our oscilloscope measurements also confirmed slower response times on the Dell, and some low levels of overshoot which the Acer did not have. The LG was pretty similar to them all as well although slightly slower again than the Acer/Asus overclocked models. The PG348Q and X34 definitely have the edge here over the other ultra-wide models, largely thanks to their overclocked 100Hz refresh rates.
 

Additional Gaming Features

Lag

For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index.

(Measurements in ms)   Total Display Lag (SMTT 2) 9.20 Pixel Response Time Element 3.90 Estimated Signal Processing Lag 5.30 Lag Classification 1

Class 1

We have provided a comparison above against other models we have tested to give an indication between screens. The screens tested are split into two measurements which are based on our overall display lag tests (using SMTT) and half the average G2G response time, as measured by the oscilloscope. The response time is split from the overall display lag and shown on the graph as the green bar. From there, the signal processing (red bar) can be provided as a good estimation.

The screen showed a total lag of only 9.20ms. Approximately 3.90ms of that can be accounted for by pixel response times, leaving an estimated signal processing lag of only 5.30ms. This is basically nothing and means the screen should be fine for all levels of gaming. Other G-sync screens to date have shown similar very low levels of lag which is pleasing. This was almost identical incidentally to the Acer Predator X34 which is again not surprising. The Dell U3415W and LG 34UM95 ultrawide screens with additional added scalers (and no G-sync module) show just over 1 frame of signal processing lag.

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 interfaces support HDCP for any encrypted and protected content

• HDMI and DisplayPort connections available. Nice to see HDMI connectivity included for modern DVD players, Blu-ray, consoles etc thanks to the use of G-sync v II here.

• 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 341 cd/m² and a good minimum luminance of 33 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 very good for an IPS-type panel at 1090:1 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 in the OSD which is brighter and cooler than our calibrated mode. May be useful though to set that mode up how you want for movies.

• Very good pixel responsiveness which can handle fast moving scenes in movies without issue. No overshoot issues which is good news as well. Just stick to the 'Normal' OD setting for optimum performance.

• 100Hz refresh rate improves fluidity of moving images and reduces perceived blurring to a degree.

• 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.

• Very little backlight leakage on our sample which is good. Some uniformity variations may be visible on darker movie scenes in darkened room conditions.

• Pretty good range range of ergonomic adjustments available from the stand, making it fairly easy to position the screen in different ways for viewing from different positions. They were stiff to move and the screen is heavy, so you won't want to move it around too often.

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

• No hardware aspect ratio control options available. Not a problem for PC movie viewing but external devices may be an issue given differing aspect ratios.

• Picture By Picture (PbP) and Picture In Picture (PiP) are not available on this model.
  
   

Conclusion

The PG348Q is another great addition to the already very popular and established ROG Swift gaming monitor series. Asus have done a nice job with the design and build of this screen and it feels like a premium high-end monitor worthy of the Republic of Gamers brand. We liked the titanium silvers and copper sections and the added red light logo projection looked fancy. Underneath that you get an established and proven panel and obviously the ultra-wide format and high resolution are two of the key selling points of models like this. You get a massive area to work with for every day uses and an interesting (and increasingly popular) format for gaming.

Gaming is where this screen is firmly aimed of course, although that's not to say it can't handle all-round uses very well. The IPS panel offers a solid default setup, strong contrast ratio and wide viewing angles that you'd hope for from this panel technology. Some might be distracted by the IPS glow on dark content on a screen this size but that's a "feature" of most current IPS panels. We appreciate the light AG coating and flicker free backlight as well which are always positive. For the gaming target market Asus have done a nice job providing some additional boosts. The 100Hz overclocked refresh rate is one of the key features here and provided improved response times, a big jump in frame rate support and improved motion clarity. We did find the screen was quite fussy with graphics card support so make sure you have a suitably powerful enough NVIDIA card to run it to avoid problems. To power a screen with this resolution and refresh rate you're going to need something beefy anyway. The additional G-sync support is of real value here, helping your system handle the demands of the screen nicely and the presence of this also ensured the input lag was extremely low. We do miss ULMB as an additional feature but in this size and format there aren't any competing models that offer a blur reduction mode yet. The bug with the overdrive control at 95 and 100Hz needs to be addressed by Asus, but even at 90Hz the screen is an excellent gaming option in this size and format.

Overall it's a very impressive all-round screen and if you're after a high end gaming ultra-wide screen this would be an excellent option. If you like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you.