Like the Acer Predator XB271HK, the ROG Swift PG27AQ is another 4K monitor with Nvidia’s G-Sync technology, which is designed to sync your Nvidia graphics card with your monitor to provide smoother motion in games.
G-Sync is designed to improve gaming at both high and low frame rates. Flatscreen PC monitors have traditionally been fixed at a certain refresh rate, such as 60Hz. If a graphics card is outputting more frames per second than the monitor can display, there is a danger that the screen will show part of one frame and part of the next, causing tearing in the image. If the graphics card can’t keep up, there will be stuttering, as the screen keeps one frame onscreen for more than one refresh cycle. G-Sync alters the monitor refresh rate on the fly to avoid both tearing and stutter.
If you have an Nvidia graphics card, G-Sync is an absolute joy. I find it makes the most difference to how much you enjoy a game when the frame rate dips below the monitor’s standard refresh rate, as the elimination of stutter makes games appear to be running at a higher frame rate than they actually are. On a screen such as this one, with a 60Hz, 3,840x2,160 panel, it’s highly likely you’ll dip below 60fps, so G-Sync makes a lot of sense.
In Dirt Rally, at the monitor’s native resolution and with Ultra detail levels, I saw between 35-40fps. As with the Acer Predator XB271HK, the game stuttered with G-Sync off, but with G-Sync turned on it looked almost as smooth as if it were running at 60fps.
Although more casual gamers such as myself are generally happy with sub-60fps frame rates as long as the game looks smooth, competitive types won’t be happy with being limited to 60Hz, as it can make the difference between the headshot landing on you or your opponent. Such hardcore online gamers would be better off with a lower-resolution, 144Hz screen such as the Acer Predator XB270HU.
Considering it’s aimed at gamers, the Asus ROG Swift PG27AQ has actually a rather subtle design. You even have the option of turning off the red lights in its base. The stand feels sturdy, the screen is height-adjustable and can rotate and tilt and turn 90 degrees clockwise into portrait mode. On the back, you get DisplayPort and HDMI inputs, a headphone socket and two USB3 ports; while these are fine for your keyboard and mouse, I missed having another couple on the side of the screen for flash drives and external hard disks.
One particularly impressive aspect is that Asus has managed the impossible and made an on-screen menu system that's easy to use. There’s a tiny red clickable joystick on the rear-right of the monitor, and this makes scrolling around the main menu and selecting options a breeze. A button next to a gamepad icon also brings up gaming-specific functions: there’s an FPS meter, a game timer and a crosshair option.
The FPS meter actually shows your screen’s current refresh rate, so only shows a game’s frame rate if you have G-Sync enabled. The Timer sets a countdown for 30, 40, 50, 60 or 90 minutes, so you can keep an eye on how long you have gone without food, water or social contact. The crosshair slaps a large gunsight in red or blue in the middle of your screen, to help with shots from the hip when you don’t have time to use a scope. I think it’s an ugly way of doing things, but Asus’ crosshairs are at least more visible than Acer’s version.
There's also a pixel overdrive option, which is meant to remove ghosting at high frame rates. Ghosting is less of a problem at 60Hz than at 144Hz, and in the Testufo benchmark I only saw very mild improvements when using overdrive, with the disadvantage of added image artefacts.
The ‘G’ button brings up the ‘GameVisual’ menu. This has six modes: Scenery, Racing, Cinema, RTS/RPG, FPS and sRGB. These have varying effects on the image; Scenery is meant to enhance greens and blues, Racing reduces input lag, Cinema enhances contrast and colour saturation, RTS/RPG jacks up saturation and contrast, while FPS enhances contrast to help you spot enemies in dark places. Finally, sRGB is designed for displaying photos.
After a reset, the screen appears to default to Racing mode. Profiling this mode with an i1 Display Pro colour calibrator, I saw that the screen was displaying 99.3% of the sRGB colour gamut, with a colour temperature of 6976K versus the ideal 6500K. This is a good result, but the Acer Predator XB271HK has it licked with its 100% and 6727K out of the box. The FPS and RTS presets were similar, while Scenery went mad for blues and greens at the expense of reds, bringing its sRGB gamut coverage down to 92.4%. Cinema had a freezing colour temperature of 10702K, making everything rather blue, while sRGB mode had a near-perfect colour temperature of 6512K, but knocked the brightness down to a dingy 112cd/m2 brightness and locked out the brightness controls.
In fact, the screen’s range of image adjustments is rather limited; depending on the selected GameVisual mode, you can adjust brightness, contrast, saturation and colour temperature, but not individual colour levels. I also noticed significant backlight bleed at the bottom-left of the screen, which is a problem common to Acer’s 4K G-Sync monitor.
There's a great deal to like about Asus’ ROG Swift PG27AQ, from its understated and well-made stand, to its excellent menu system and beautifully smooth 4K gameplay with G-Sync. However, Acer’s Predator XB271HK has the same advantages and better overall image quality. It's also a useful £60 cheaper, so remains my 4K G-Sync choice.
Screen size: 27in, Resolution: 3,840x2,160, Screen technology: IPS, Refresh rate: 60Hz