Author: Adam Simmons

Date published: December 9th 2015



The 3840 x 2160 ‘4K’ UHD (Ultra High Definition) resolution can provide a visually stunning gaming experience and is very useful as far as productivity is concerned. But unless you have a monstrously powerful system, maintaining a solid 60fps is very difficult indeed on modern games titles. For UHD monitors with a static 60Hz refresh rate, this means the user will experience stuttering or tearing as the frame rate of the content departs from the refresh rate of the game. The ASUS ROG (Republic Of Gamers) SWIFT PG27AQ has an ace up its sleeve in the form of Nvidia G-SYNC, a technology that allows the refresh rate of the monitor to dynamically adjust to match the frame rate of the content. We see what this addition brings to the table and also how the monitor itself performs in a range of ‘real world’ scenarios.





The monitor uses a 27” ‘4K’ UHD panel from AU Optronics. This makes use of AHVA (Advanced Hyper Viewing Angle) technology and is therefore an IPS-type panel. The monitor supports 10-bit colour by means of 8-bits per channel + FRC dithering. A 4ms grey to grey response time is specified and as usual this is adjustable with various ‘TraceFree’ pixel overdrive settings. We have highlighted some key talking points in blue below.

Screen size: 27 inches

Panel type: AU Optronics M270QAN01 AHVA (Advanced Hyper Viewing Angle) LCD

Native resolution: 3840 x 2160

Typical maximum brightness: 300 cd/m²

Colour support: 1.07 billion (8-bits per subpixel plus dithering)

Response time (G2G): 4ms

Refresh rate: 60Hz (variable, with G-SYNC)

Weight: 7.2kg

Contrast ratio: 1,000:1 (20m:1 Dynamic Contrast)

Viewing angle: 178º horizontal, 178º vertical

Power consumption: <90W

Backlight: WLED (White Light Emitting Diode)

Typical price as reviewed: Not yet available (expected during Q1 2016)

From the front this monitor has a sleek and angular design. The bezels are very thin, despite having the ‘2-stage’ design seen on quite a few modern monitors. When the screen is switched off all you can really see in the way of bezel is the hard outer component of around 8mm at the top and sides, made from matte plastic. This includes the very thin ‘rim’ that surrounds it. Once the screen is switched on, it becomes apparent that there is also a very thin panel border of around 2mm (if that) at the top and sides that blends in seamlessly when the monitor is switched off but is visible around the image when it is switched on. Of course, this panel border is very thin and hardly worth sweating over – and the total bezel thickness counting both components is at most 10mm (0.39 inches). The bottom bezel is thicker but still rather slender, especially for a bottom bezel, at around 15mm (0.59 inches) including both bezel components. Other interesting points to note at the front include the ‘very light matte’ screen surface, explored later and the ‘Light in Motion’ feature. This includes a red LED rim around the base of the stand neck and also a red ROG cloak motif logo, again illuminated by LEDs. When fully lit up, the monitor looks sort of evil and as if it is trying to identify itself as a monitor of the ‘Dark side’. It’s a fairly intense red rather than orange as it appears on the photo. These ‘Light in Motion’ LEDs can be switched off in the OSD (On Screen Display) if preferred.





The OSD is controlled by a 5-way (4 directions plus click) joystick and some additional buttons which run down the rear side of the right bezel, near the bottom. There is also a power LED to indicate the power status of the monitor, which is a thin rectangle that runs from front to back along the underside of the bottom bezel. Only a small section is therefore visible from the front. This glows red when G-SYNC is active (even if you’re just on the desktop), white when the monitor is working at a fixed refresh rate with G-SYNC disabled and amber when the monitor is on standby (low power state). When you switch the monitor ‘off’ using the power button, the LED also turns off. The video below runs through the functionality of this OSD.





From the side the monitor is quite slender, around 22mm (0.87 inches) at thinnest point but lumping out towards the centre where the stand attaches. The stand offers full ergonomic flexibility; tilt (5° forwards, 20° backwards), height adjustment (120mm or 4.72 inches), swivel (60° left and right) and pivot (90° rotation clockwise into portrait). The overall build quality of the stand and product itself is certainly nice – it feels rather solid and well-built as you would hope given the asking price. For reference the stand base is ~240mm (9.45 inches) deep. At the lowest height, the bottom edge of the screen clears the desk by ~78mm (3.07 inches) with the top of the screen ~437mm (17.20 inches) above the desk.





The rear of the stand has an interesting angular design with matte black plastic used in favour of glossy plastics. This matte black plastic is used on the bezels and stand as well. The top and bottom areas of the screen, at the rear, are textured with a sort of triangle pattern. The stand attaches by 100 x 100mm VESA and can be removed by taking off the rubber screw covers and removing the screws beneath. An alternative VESA 100 stand or mount can then be used. There is a cable-tidy mechanism towards the bottom of the stand neck and an interesting arrangements of down-firing ports running up and then down the top sides of the bottom triangular area of the stand.







From left to right the ports are; DC power input (external power brick), 3.5mm headphone jack, DP 1.2 input, HDMI, USB 3.0 upstream, 2 USB 3.0 downstream ports, a service port (for ASUS service centre use) and a Kensington lock slot. Standard cables include; a DP cable, HDMI cable, USB 3.0 upstream cable, and a power cable (and adaptor). There are also 2 x 2W stereo speakers which provide basic sound output. The clarity of these speakers is fairly good for 2W stereo speakers, with fairly clear treble and mid-tones. The ‘bassiness’ is reasonable in places too – they provide a generally less ‘tinny’ sound than integrated monitor speakers usually do. Whilst they aren’t going to get the pulses of audiophiles racing, they are certainly useable. Good for those moments where you don’t want to don that pair of headphones you have connected to the PC, for whatever reason.





The monitor uses a very light matte screen surface, with a fairly low haze value. This sort of screen surface preserves vibrancy and clarity better than stronger/heavier matte surfaces. The screen surface does not have the strong ‘smeary’ layered grain of some matte surfaces, although there is a bit of a grainy look to white and other light colours. In other words, the surface texture is not as smooth as we’ve seen on some other ‘very light’ matte screen surfaces despite the low haze value. The low haze value does in itself still improve the potential vibrancy and overall clarity regardless of this.







The usual RGB (Red, Green and Blue) stripe subpixel layout is used by this monitor. This is the most common subpixel layout and the default expected by modern Operating Systems such as Microsoft Windows and Apple’s MacOS. There is therefore no need to worry about ‘fringing text’ as a Mac user or having to run ‘ClearType’ as a Windows user. Still, you may still want to run ‘ClearType’ to fine-tune according to preferences.





The PG27AQ features a number of ‘GameVisual’ presets; ‘Scenery Mode’, ‘Racing Mode’, ‘Cinema Mode’, ‘RTS/RPG Mode’, ‘FPS Mode’ and ‘sRGB Mode’. There are also a number of other interesting options in the OSD, including a ‘Blue Light Filter’, a ‘Low Blue Light’ setting which allows the user to set the monitor to one of 4 levels of increased blue light reduction. In the table below we look at a range of different settings in the OSD and how they affect the general image characteristics. Readings for the white point and central gamma are also provided, as recorded using a Spyder5ELITE colorimeter. We also list some of the OSD settings that are available with some of these settings but not others.

Our test system uses Windows 10 and an Nvidia GTX 970, with the monitor installed in its ‘plug and play’ state without any additional drivers or ICC profiles loaded. The screen was connected via DP 1.2. Note that DP 1.2 is required to run the monitor at its full native resolution, at 60Hz. It’s also required (alongside a compatible Nvidia GPU) to make use of G-SYNC. DP 1.1 is limited to 3840 x 2160 @30Hz, whilst HDMI (version 1.4 used by the monitor) is technically limited to 3840 x 2160 @30Hz – although 24Hz is actually listed in the resolution list instead. 1920 x 1080 @ 60Hz is also supported via HDMI. Unless otherwise stated assume default settings were used, with the exception of our ‘Test Settings’ with certain changes made as explored later.

Out of the box this monitor was quite bright, although not overwhelmingly so as the brightness control in the OSD is set to ‘80’ rather than ‘100’. ASUS have included a number of ‘GameVisual’ presets rather than ‘Splendid’ modes with this monitor. By default it comes set to ‘Racing’ mode. Aside from the brightness and the colour temperature being a bit high and therefore things looking a bit ‘cool’ with a slight blue dominance, things are nicely balanced. We therefore used this as a basis for our ‘Test Settings’, but made a few tweaks as explored later. The image below shows gamma tracking under our ‘Test Settings’ – as you can see, things track very closely to the curve in this representation.



Gamma test settings Impressively, the gamma tracking clings tightly to the standard ‘2.2’ curve regardless of the ‘GameVisual’ preset used. These alternative ‘GameVisual’ modes are not really as desirable as the standard ‘Racing Mode’ default, though, as they selectively oversaturate colours or dull the image whilst locking off access to brightness and other basic image controls. In the ‘Racing Mode’ you also have access to ‘Blue Light Filter’ settings which are applied on top. These allow you to enforce various levels of blue light reduction and work as you’d hope – effectively reducing blue light output. As usual, they do this by lowering the blue colour channel to lower colour temperature and give the image a warmer appearance. The strongest setting (‘Level 4’) also enforces a lower brightness, which reduces overall light output including that in the blue region. You can manually adjust the brightness levels to suit for ‘Level 1’ to ‘Level 3’. Note that you can also adjust the colour channels after enforcing one of these ‘Blue Light Filter’ settings, but such changes can enhance or nullify the effect. If you then select one of the ‘Blue Light Filter’ settings again it will overwrite any changes you’ve made to the colour channels. ‘Level 0’ means the ‘Blue Light Filter’ setting is deactivated. Rather annoyingly, any manual adjustment you make to the colour channels are reset once any ‘Blue Light Filter’ setting is used. So you can’t activate one of these settings for relaxing evening viewing and then quickly return to your manual adjustments for a 6500K white point (or whatever you’re targeting) in the daytime. You’d have to dial in your manual adjustments again. These settings are still nice to have, but having them as a separate thing that doesn’t overwrite colour channel adjustments would have been preferable.



Test Settings For our ‘Test Settings’, we used the factory default ‘Racing Mode’ but significantly reduced the brightness. We also slightly reduced the green and blue colour channels to counteract the cool tint (without introducing a green tint instead). The settings below were suitable for our unit and should be used as a guide, but be aware that individual units vary. Any settings not mentioned here were left at default. We’ve also included the ‘OD’ setting used in the review, just for reference.





Brightness= 53 (according to preferences and lighting) Brightness= 53 (according to preferences and lighting) R= 100 G= 98 B= 97 OD= OFF

Contrast and brightness Contrast ratios We used a highly accurate light meter (Konica Minolta CS-200) to measure the luminance of white and black using various monitor settings. From these readings static contrast ratios were calculated, as shown in the table below. Values for the highest white luminance, lowest black luminance and highest contrast ratio recorded are highlighted in blue. The results under our ‘Test Settings’ are highlighted in black. With the exception of the ‘Test Settings’, assume anything not mentioned was left at default. Monitor Settings White luminance (cd/m²) Black luminance (cd/m²) Contrast ratio (x:1) 100% brightness 263 0.23 1143 80% brightness (Factory Defaults) 223 0.20 1115 60% brightness 183 0.16 1144 40% brightness 138 0.12 1150 20% brightness 90 0.08 1125 0% brightness 37 0.03 1233 RTS/RPG Mode 225 0.20 1125 FPS Mode 224 0.20 1120 Game 279 0.25 1116 sRGB Mode 107 0.10 1070 Blue Light Filter = Level 1 221 0.19 1163 Blue Light Filter = Level 2 219 0.19 1153 Blue Light Filter = Level 3 219 0.19 1153 Blue Light Filter = Level 4 77 0.07 1100 Test Settings 160 0.15 1067

The PG27AQ produced an average static contrast of 1152:1 with only brightness adjusted, which is good. Impressively, it maintained strong contrast with all of the setting combinations we tested. Even the ‘Blue Light Filter’ settings, which do usually reduce contrast, had a negligible effect here. The adjustment made to our test settings dropped the contrast slightly to a still respectable 1070:1. The lowest white luminance recorded on this table was a fairly low 37cd/m² whilst the maximum was 263 cd/m², falling a bit short of the specified 300 cd/m². Very few users would require a brightness anywhere near this high, though. The luminance adjustment range for the monitor based on these figures is 226 cd/m².





PWM (Pulse Width Modulation)

The monitor uses DC (Direct Current) and does not use PWM (Pulse Width Modulation) at any brightness level. The backlight is therefore ‘flicker-free’, as advertised, which will come as welcome news to those sensitive to flickering or other side-effects of PWM usage such as PWM artifacts.





Luminance uniformity