Today’s comparison group has a little of everything. G-Sync is represented by the BenQ XL2420G and AOC G2460PG. FreeSync-capable panels include the BenQ XL2730Z and Acer XG270HU. Rounding out the line-up is Planar’s IX2850, which is a comparable Ultra HD screen with good performance and a relatively low price.
If the XB280HK offered blur reduction, we’d be concerned by its low max output. It doesn't though, so we aren’t. A result of 270.8707cd/m2 isn’t as high as the others, but unless you’re playing outside on your deck in Florida, it’s high enough.
A lower backlight level translates to better blacks than the rest of the group. Unfortunately, it doesn't signal better contrast.
A 777.2:1 contrast ratio isn’t terrible. However, it does lag behind the norm a bit. Planar uses the same panel part in its IX2850 and manages to coax a little more from it. This is, however, pretty close to what we’ve recorded from all of the 28-inch UHD/TN panels reviewed on Tom's Hardware. Given a choice, we’d choose the higher contrast offered by the top two screens (even though the extra pixels are nice).
Uncalibrated – Minimum Backlight Level
The backlight goes very low on the XB280HK, covering a range of 239cd/m2. A reading of 31.0382cd/m2 is pretty dim. If you click back to the previous page, though, you’ll see our brightness settings for 80 and 120cd/m2, which are much more useful in dark rooms.
Of course, that results in class-leading black levels. Too bad Acer’s contrast is not high enough to take advantage of this.
Contrast prior to calibration lands at the bottom of the group, regardless of backlight level. Still, there is improvement ahead. Check out our calibrated and ANSI results below.
After Calibration to 200cd/m2
Calibration helps the black level and contrast numbers a little. Remember that none of the Ultra HD TN-based panels we’ve tested can match the results of lower-resolution glass in these tests.
It isn’t often we can increase contrast by calibration. Thanks to the XB280HK’s well-designed OSD controls, it becomes an exception to the norm. Acer still can't rival the BenQ screens, but it comes closer to Planar's solution at least.
ANSI Contrast Ratio
The final result is also the most impressive. It’s rare that ANSI contrast comes out higher than the on/off number. Apparently, a test that resembles actual content brings the XB280HK closer to the top of the pack.
Our takeaway from these benchmarks is that, while this panel isn’t exceptionally bright or contrasty, it holds its own. If you want Ultra HD and G-Sync in the same monitor, you won’t feel like you’ve settled by choosing Acer's XB280HK.
Grayscale Tracking
Our grayscale and gamma tests are described in detail here.
While the XB280HK isn’t premium-priced relative to competing Ultra HD screens, it is an expensive gaming monitor. For your money, you’re getting decent grayscale performance out of the box. In the Standard picture mode, you really don’t have to make any adjustments to enjoy accurate performance. At 100 percent, the white point starts to go a little blue. But upping the Contrast control one click will fix that.
An instrumented calibration brings the errors down to almost nothing with just a few tweaks. The result is fantastic.
Here is our comparison group:
The XB280HK takes top honors for out-of-box grayscale performance. We expect that a majority of gamers will not calibrate their monitors, so if accuracy is important to you, there are few better choices in the G-Sync or FreeSync segment.
The AOC takes first place by the slimmest of margins. A difference of .04dE is essentially a wash.
Gamma Response
Gamma tracking is not quite as flat as we’d like. At least the trace is pretty linear until the 90 percent mark, where it takes a dive below the line (meaning it’s a little too bright). Visually, the error doesn’t impact picture quality much. Still though, some gaming screens perform better. Calibration doesn’t affect this result, so there’s no help there. And the presets are too far apart to make a difference. Your best bet is the 2.2 setting.
Here is our comparison group again:
Since Acer’s other gaming screen, the XG270HU, takes the top spot, we have to conclude that the panel part is what’s holding our XB280HK sample back from a better score.
We calculate gamma deviation by simply expressing the difference from 2.2 as a percentage.
Since a majority of the gamma trace rides above the line, our measured average is a slightly-dark 2.32. We tried the 1.9 preset, but that’s way too light to help. We are picking nits here; this is only a small flaw.
Color Gamut Performance
For details on our color gamut testing and volume calculations, please click here.
Standard mode is the XB280HK’s default setting, and it provides decent color gamut accuracy. The problems occur on the red/magenta/blue side of the triangle. Blue is over-saturated at all levels, along with magenta. Red is fine at the 20, 40, an