User Color Temperature: R100, G97, B99. Brightness 38 for 180 nits.

The Y27q-20 has a very good range of brightness adjustment, from 60 nits at the low end to 363 nits max. Lenovo only claims a peak brightness of 350 cd/m^2, which, while not as bright as some of the other monitors I've reviewed that reach 400+ nits, should be sufficient for most users. I've found 180 nits serves as a comfortable middle ground for most viewing conditions, either day or night, so that brightness is my calibration target.

Contrast is low, even for an IPS display. This wasn't unexpected; the Lenovo Y27q-20 uses the same LG nano-IPS panel found in the 27GL850, the Dell 2721DGF, and the ViewSonic XG270QG, all of which have poor contrast. My sample of the XG270QG was particularly bad at only 700:1, so the Lenovo at least does better than that.

ASUS's VG27AQ is a similarly priced QHD competitor to the Y27q-20, and its 1110:1 contrast ratio bests the Lenovo. But how much difference does that actually make? The shot below compares the black levels of the two screens when both are calibrated to 180 nits:

Both screens, happily, have minimal backlight bleed, but the VG27AQ does, indeed, produce darker blacks. Neither looks great in the dark.

The Y27q-20 uses a wide gamut panel, and that'll most likely be the very first thing you notice about the screen. Reds, especially, are remarkably deep and vivid due to the PFS phosphor, so the Lenovo actually extends slightly beyond the P3 color space for red saturation.

I was concerned that the extended gamut would cause most sRGB mastered content to look unnaturally saturated, with skin tones going hyper-red and everything else blown out like a Walmart display model, but that's not the case with the Y27q-20. Only the most saturated colors are extended, but moderately saturated tones are kept well controlled; HCFR uses the ColorChecker Classic patterns to test colors like Dark Skin, Light Skin, Blue Sky, and Foliage, and I measured an average delta E of only 2.7 for the Lenovo. Skin tones do look a little punchier than on a standard gamut panel, but nothing is so outrageously inaccurate that you can't just leave the panel in the extended mode.

If you do need clamped primaries, though, Lenovo does offer an sRGB mode in the OSD.

More than likely, you're looking at this review on a standard gamut panel, so it's impossible to show you exactly what an extended gamut looks like, but here's an attempt:

Both the Lenovo and ASUS are showing pure red here, but seeing the two side-by-side really illustrates just how not-red sRGB red really is.

But now on to grayscale performance:

Using only the OSD color temperature controls (no software calibration), I couldn't quite bring the three primaries together throughout the full grayscale range. The best I could achieve was a slightly warmer median color temperature of 6442 K compared to the target of 6500 K. Quite close, but other screens do slightly better.

The elevated red and green levels above 50% white lead to a steadily increasing delta E as the brightness ramps, but most values are below two, so the Lenovo performs well here. An average delta E of only 1.3 is a good result for what can be achieved with just a few OSD modifications.

Lenovo doesn't offer any gamma adjustment in the OSD, which is disappointing, but otherwise they've done an excellent job of tracking the sRGB gamma curve. I prefer to use the more television focused BT.1886 gamma 2.4, so some options would be nice!

If you need to work in the sRGB color space, the Y27q-20 does have an sRGB mode in the OSD. When enabled, every user color control is locked, even brightness, so we're at the mercy of Lenovo to provide us an accurate mode, and unfortunately, they don't hit the mark here.

The primaries are indeed clamped to the sRGB color space, but as you can see below, the white point is too blue, around 6850 K, which shifts all the saturations and ColorChecker measurements off target. This would be easy enough to correct with some color controls, but I get the engineering dilemma here: you can't offer a true sRGB mode if you allow users to monkey around with it, but if you're going to lock everything down, you have to get it right.

With the too-cool color temperature, grayscale delta E's steadily rise as the percent white increases, leading to 3.0 average, which is worse than in the unclamped mode.

Lenovo also somehow manages to track sRGB gamma worse in their sRGB mode than in their regular mode.

The anti-glare film on the Y27q-20 is very good, even better than the VG27AQ's film. Whites look white throuhout the screen, with no rainbow speckling or shimmering. Only at extreme angles, forty degrees or more, does a little bit of speckling become apparent.

I'm still waiting for a proper anti-reflective coating, though.

These gradient patches show the monitor has no trouble showing typical 8-bit gradients without banding, but I haven't yet seen a single monitor that has trouble with this. Most complaints of banding are actually complaints about JPEG compression or video compression artifacts.

Unusually low gamma (which actually makes the darkest parts of the images quite bright) can show banding artifacts that you typically wouldn't see.

Much like the ViewSonic XG270, the Y27q-20 shows significant vignetting on the left and right side of the panel. When calibrated to 180 nits at the center, the right edge is only producing 133 nits, and the top-left corner is even worse: 125 nits. This is easily visible in normal content, not just in this exaggerated shot.

Backlight bleed is acceptable. When I first took the monitor out of the box, the bleed along the bottom edge was fairly apparent, but after several days, the panel mellowed out. There's still a bit of bleed in the bottom left corner, but I'm pretty pleased with this after my bad experience with the ViewSonic XG270QG, which shares the same nano-IPS panel as the Y27q-20.

Viewing angles are very good, with limited gamma and color shifts as the angle gets more extreme. The panel does darken at large angles, but for most viewing conditions, IPS displays do well.

IPS glow is no better or worse than other IPS displays I've reviewed in the past; this is an inherent limitation of the technology, so it's something to be aware of before you purchase your first IPS.

To measure input lag, I use a custom UE4 build that runs at 1000 FPS and can rise from black to white based on a keypress. I have a micro-controller initate the keypress and record the response over 800 times. Because I'm measuring at a single location, the results take the form of a uniform distribution of rise times spanning one 165 Hz frame plus some additional USB overhead. But the important measurement is the fastest response, which for the Lenovo I found to be 2.19 ms. My CRT, which does no processing, had a best response of 1.58 ms, so the estimated processing lag for the Y27q-20 is the difference: 0.61 ms. Great result.

So far, the differences between monitors haven't been substantial; every monitor tested has an estimated processing delay of less than one millisecond.

Lenovo provides three overdrive modes for the Y27q-20: Off, Normal, and Extreme. These Frog Pursuit shots illustrate the difference at 165 FPS:

Off really is off; zero transitions show overshoot, so we get a glimpse of the panel's native response. But there's little reason to leave performance on the table, so Normal, at high refresh rates, introduces a modest amount of overshoot to help speed up some of the slower transitions. Lenovo claims a 3 ms response time average for Normal, which we can look into later.

Extreme is yet another example of a manufacturer implementing a useless and terrible overdrive mode specifically for the purpose of being able to claim a one millisecond response time in marketing materials.

At 85 FPS, still in the variable refresh range, it's much harder to pick a winner between Off and Normal. The slight overshoot that was minimally invasive at 165 FPS now lingers longer and thus becomes easier to spot at lower framerates, so we get slight inverse ghosts following behind each of the frogs. And now cyan, magenta, and yellow ghosts appear behind the RGB traffic lights.

Due to the longer frametime at 85 FPS (11.8 ms), Extreme's already insane overshoot lingers longer, so the inverse ghosts are now much worse. But, of course, many of these gray-to-gray transitions first reach their target level in around one millisecond, so marketing check-box ticked!

Here are the CAD scores for the three overdrive modes plotted across the full variable refresh rate range. CAD now more harshly penalizes overshoot, and the Extreme mode shows that off. A max CAD of 200 is really bad, but it's not quite as shameful as ViewSonic's Fastest mode on the XG270, which hit 340!

Let's drop Extreme and look at the other, more reasonable modes:

I have Normal performing better than Off at every framerate, but the scores do nearly converge at 85 FPS. Even with the new CAD overshoot penalty, Normal slightly bests Off at this low framerate. That may be a bit unexpected based on the 85 FPS pursuit shots above, but while that lingering overshoot hurts the Normal mode's score, it's more than made up for with slightly goosed LCD fall times. With overdrive Off, the average CAD for falling transitions is 61.6, slightly higher than the same measurement with overdrive set to Normal, 58.7.

If you're very sensitive to overshoot, you may want to swap to Off if your games are routinely running between 75 to 90 FPS, but Normal is the better mode overall.

Next up is the full refresh rate gamut of Frog Pursuit images taken with Overdrive set to Normal:

With the Lenovo added in, I now have new CAD data for six monitors: this Y27q-20, ASUS's VG27AQ and VG279QM, the LG 24GM79G, and ViewSonic's XG270 and XG270QG.

The first thing to note is just how demonstrably the Y27q-20 beats the VG27AQ. The ASUS was never a super fast QHD screen, but LG's nano-IPS panel is much faster. But then look at the Lenovo hanging with the two fast IPS 240 Hz+ monitors from ASUS and ViewSonic! This is a great achievement for a QHD screen. At high framerates, the Y27q-20 scores on par with the Viewsonic and is only slightly behind the VG279QM. But without any sort of variable overdrive, it does fall a bit behind the XG270 at that 85 FPS mark.

So at a roughly similar price to the 240 Hz+ FHD screens, the Lenovo is offering the same-ish performance at commonly attainable framerates, higher resolution, and a wider color gamut. I really like both the VG279QM and XG270 for various reasons, but the Y27q-20 puts in perspective how overpriced they are.