BenQ says that the maximum light output of the XL2720T is 300 nits, but the most I could record is 252 nits while not totally crushing whites. It might be possible to set the contrast to 100 and record a higher number, but with that setting the top white shades, from around 230 until 255, all blend into a single shade. No one would ever use a display this way, so it’s a bit impractical for me to measure them this way. The lowest white level I could get was 93 nits, which helps to explain the contrast ratio issue on the sRGB test. If we are targeting 80 nits, and the lowest level the display can natively do is 93 nits, then the video card LUT has to be lowered to bring that brightness down. Anytime you lower the peak of the LUT, you then start losing contrast range, which is why we try to get the monitor set as close as possible before calibration, or use DDC to have it automatically do it correctly.

White Level -  XR Pro, Xrite i1D2 and XR i1DPro

The black level was fine on the XL2720T, though not exceptional as TN isn’t known for being great at blocking out light. It isn’t a bad number, but black level is really all about contrast ratio and on its own doesn’t mean much unless we also know the white value.

Black Level - XR Pro, Xrite i1D2 and XR i1DPro

The contrast ratio on the BenQ comes out at right around 820:1 at maximum or minimum light level. The lower number we saw on the sRGB calibration was due to targeting a light output level below what the monitor can do natively. If you aren’t trying to go below the 95 nits light level that I saw on the white testing, you will get a contrast ratio right around 820:1 from the XL2720T.

Contrast Ratio -  XR Pro, Xrite i1D2 and XR i1DPro

The BenQ XL2720T also does well on power usage, consuming very little at maximum or minimum backlight levels. Other than the Acer touchscreen model, the BenQ is the most efficient monitor for which I have calculated the Candelas per Watt number, which takes into account screen size, power use, and light output to normalize the data. I have a feeling the BenQ benefits by having a lower resolution 27” panel than most of the 27” monitors I’ve tested, but with the small number of data points I have so far that is all conjecture at the moment. Whatever the cause of it, the power use of the BenQ is very low.

LCD Power Draw (Kill-A-Watt)

Candelas per Watt

Display Uniformity Gaming Use Comments and Lag Tests
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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. Reply
  • 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...
    Reply
  • 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.
    Reply
  • 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.
    Reply
  • 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.
    Reply
  • 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. Reply
  • 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!
    Reply
  • 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. Reply
  • 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.
    Reply
  • 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
    Reply

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