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Brightness & Contrast
To read about our monitor tests in depth, please check out Display Testing Explained: How We Test Monitors and TVs.Brightness and Contrast testing are covered on page two.
Uncalibrated – Maximum Backlight Level
Today’s group includes the 25” 240Hz monitors we’ve already reviewed: Asus’ PG258Q, Acer’s XB252Q, and AOC’s AG251FZ. We’ve also included Asus’ PG248Q. Rounding out the comparison is Dell’s S2417DG which offers G-Sync and QHD resolution. All the panels use TN parts.
The AU Optronics part is distinguished not only by its speed, but by its high brightness. That makes ULMB a far more viable option for gamers who believe G-Sync may cause control latency. While we can’t confirm this in our tests, at least Alienware is making blur-reduction a useful function rather than just an afterthought.
Black levels are merely average for the category and therefore so is contrast. None of the screens can hold a candle to a VA panel; but no VA panel can match the speed of these monitors. So, it comes down to personal preference and performance priority. What matters most to you?
Uncalibrated – Minimum Backlight Level
The 25” Acer and Asus screens maintain high minimum brightness values making them less-suitable for dark-room gaming than the AW2518H. Its low end of 66.4358cd/m2 is just about perfect for gameplay when all the lights are off. Black levels remain consistent as does the contrast value at 951.6:1 This is respectable performance.
After Calibration to 200cd/m2
ULMB only costs a mere 23% brightness which is a good thing. An even better thing is that you can set the slider independently for each mode so it’s easy to have the same output level regardless of your other settings. While we’ll always opt for G-Sync, there are players who prefer ULMB in some situations. The AW2518H makes that possible. In that way, it’s equal to the PG258Q and XB252Q.
Our RGB and contrast slider adjustments have only lowered sequential contrast by a scant 2%, barely visible to the naked eye. However, ULMB has a greater impact, reducing the number by an additional 15%. While it takes the black level down to a top-place finish, output reduction is larger. In highly detailed games, ULMB may not be the best choice. You don’t want to reduce definition in small objects; they may just be a deadly opponent that you’ve identified too late.
ANSI Contrast Ratio
When ANSI contrast is this close to sequential, you know a premium panel part is in use. Despite its old-school TN technology, the AW2518H sports excellent performance thanks to good engineering and quality control. The grid polarizer is mounted with precision, which keeps intra-image contrast high. It won’t be mistaken for VA, but among TN and IPS monitors, 948.5:1 is a very good result in this test.
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