BenQ XL2720T Gaming Monitor Reviewed
by Chris Heinonen on June 17, 2013 4:35 PM ESTLooking at the white uniformity of the BenQ XL2720T, we see a large drop-off in the upper left, and another drop on the right side that isn’t quite as drastic. I like to see everything stay within 5% of the center value ideally, which means 180-220 nits if the center is at 200 nits, but this one measurement drops down to 167 nits and is clearly darker. The right side only drops down to 172 nits, but that is still fairly low. Most of the display stays within that 5% threshold, but on the edges it has an issue.
With the black uniformity, we see some bright corners on the left side, and the surrounding numbers are much lower than they are, and with an all-black screen it is quite easy to tell the difference. The center actually has the highest black level of anywhere other than that one bright corner.
The contrast uniformity on the display varies by a lot. The center comes in at 795:1 (not quite the 820:1 we measured earlier, but the black reading changing by as little as 0.001 nits can influence this highly), but the rest of the monitor swings from as low as 754:1 to as high as 946:1. With contrast ratio higher is going to be better, but looking at the chart really shows that the overall uniformity of the white and black levels on the BenQ isn’t ideal.
The grayscale uniformity shows this as well. The center is still quite good, coming in at a dE2000 of 0.92. The reason for the higher value here than on the calibration page is that uniformity testing uses 0%, 20%, 40%, 60%, 80%, and 100% values, not 0-100% in 5% increments. Since the 0% value is the highest, it has added weight here, but doing uniformity testing with all 21 values would be unreasonably time consuming to do. We see that the dE2000 rises up to 3.46 in that hot-spot on the left side of the screen, and has a few other areas above 2.0 as well. Most of the screen is still good, and as I said these numbers might be lower if I measured 21 points per location, but that’s still a large difference on the display.
With the colorchecker uniformity, we see the same issues, only worse. Since the colorchecker starts with a higher error than the grayscale, we see that many points on the screen have managed to rise above 3.0, which is considered not visible to the human eye when in motion. We also see that corners are measuring really well, while the center of the screen is further off. This is a bit strange, but overall the uniformity isn’t as strong as with other displays.
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ViperV990 - Monday, June 17, 2013 - link
I'm not seeing any mentions of Lightboost (strobing backlight). IMO that is the most important selling point of this monitor. If you think the differences between 60Hz to 120Hz is huge, you'll be blown away by the differences between Lightboost on and off.ViperV990 - Monday, June 17, 2013 - link
If you're not familiar with Lightboost, this is a good place to start reading up:http://www.blurbusters.com/zero-motion-blur/lightb...
A5 - Monday, June 17, 2013 - link
Strobing backlight is the same thing "240 Hz" LCD TVs use to achieve their effect.Is the difference noticeable in anything besides specifically designed motion resolution tests?
Considering most games have motion blur shaders on these days anyways, I hardly see the point.
chizow - Monday, June 17, 2013 - link
No, it's not the same thing as 240Hz LCD TVs, instead of counting an inserted black frame or interpolated frame as a new "frame" to accomplish 240Hz, the backlight pulse ONLY strobes when an actual new frame is ready to be displayed, resulting in MUCH less image blur while allowing intermediate or transitional frames to clear.So instead of a constantly lit, muddy picture full of transitional ghosting and image retention, you get a crisp, true 120Hz image that pulses double-bright only when a true, new frame is ready to be displayed. Really a huge difference, it's why many fast-paced gamers won't go back to anything else but a 120Hz LightBoost panel, despite some of the trade-offs like 1080p limitation, TN panels etc.
Galford007 - Tuesday, June 18, 2013 - link
@A5, @Chizow:I initially thought this "lightboost" thing was a gimmick but I recently bought an ASUS 144hz lightboost-capable monitor (VG248QE, ~$300 on Newegg) and I'm now a true believer. It's capable of 3D but I prefer to use it in 2D lightboost mode. There ARE some tradeoffs such as loss of color accuracy and brightness, but it looks AMAZING, especially in games like Battlefield 3. In order to get the full effect, you need to match in-game FPS with the refresh rate, so even with a GTX 580 I have to turn BF3 settings to low and 100Hz. The graphics still look pretty good but it's worth the tradeoff IMO. I'd definitely recommend to check out the Blurbusters site for more info on the technology (as ViperV990 suggested). Basically this "lightboost" thing is a happy accident, but I'm sure it'll gain traction soon.
chizow - Tuesday, June 18, 2013 - link
Oh and blur shaders are a huge part of the problem, designed to cover up the muddy ugliness that is the norm with 60Hz non-LightBoost monitors. You'll want to turn all that crap off if you're using a 120Hz panel with LightBoost, if you value a clear, fluid image anyways.mdrejhon - Tuesday, June 18, 2013 - link
TFTCentral's Motion Blur Reduction Backlights (Including LightBoost)http://www.tftcentral.co.uk/articles/motion_blur.h...
They said that LightBoost outperformed all scanning backlights they have ever tested.
A good 60Hz vs 120Hz vs LightBoost image comparision is:
http://www.blurbusters.com/faq/60vs120vsLB
There's also a large LightBoost FAQ at:
http://www.blurbusters.com/zero-motion-blur/lightb...
Also, see the improved Battlefield3 score graphs at:
http://www.blurbusters.com/zero-motion-blur/testim...
You will notice that about 20% of amazon.com customer reviews for the ASUS VG248QE monitor (popular LightBoost monitor) have rave reviews about the LightBoost motion blur elimination. Go check out the rave LightBoost reviews:
http://www.amazon.com/VG248QE-24-Inch-Screen-LED-l...
Within that webpage, hit Control+F and find "LightBoost" in all the Amazon customer reviews!
mutantmagnet - Monday, June 17, 2013 - link
I clicked this article just to see if they were going talk about this as well. They talk about sacrificing color correction for smoother gameplay as a mundane thing which isn't the case.cheinonen - Tuesday, June 18, 2013 - link
I've been testing Lightboost today after reading the comments and will go in and add some commentary on it. Using lightboost for 2D is undocumented (at least as far as BenQ is involved) and requires some messing around with settings, and never came up in my discussions with BenQ as something to be aware of with the display. I didn't notice any commentary on it online until now either, which is how it didn't get mentioned.Also, I have no idea how the stats didn't make it into the review, that's just a dumb mistake on my part that needs to be remedied here really quick.
mdrejhon - Tuesday, June 18, 2013 - link
BTW, great to recognize the attention needed because LightBoost apparently now sells a significant fraction of 120Hz monitors ever since the extreme enthusiast community figured out how to use it (without needing 3D).Some good news -- ToastyX is developing a new LightBoost utility (I'm beta testing) that makes it easy to enable/disable. No inf/reg files -- just an easy utility. Finally, it will be easy to enable/disable LightBoost -- with a hotkey shortcut! -- even on multiple monitor setups.
Some tips:
- If you don't have a Titan/780, then Lightboost often benefits older games a lot more (try source engine games, Quake Live, test with both VSYNC ON, and with VSYNC OFF), as it behaves like a 120Hz CRT and needs 120fps to make it sing.
- XL2720T Lightboost color seems better with drivers 320.18
- For picture adjustments, see LightBoost FAQ at http://www.blurbusters.com/zero-motion-blur/lightb...
- I've sent you an email with a link to a new motion test