Measuring Input Lag of G-SYNC! – Preview Part #2

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In G-SYNC Preview #2, we are the world’s first to measure the input lag of G-SYNC using an innovative testing technique.

We found what we expected, plus we found a few unexpected surprises, with a good, happy ending! Go check it out.

We also touch upon the LightBoost sequel, called Ultra Low Motion Blur (ULMB).

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4 Responses to Measuring Input Lag of G-SYNC! – Preview Part #2

  1. wmailman says:

    You’d get a similar reduction in input lag from locking your framerate one or two below your refresh rate on a normal monitor with Vsync on. I’ve been doing that for ages and have never had an issue. You go from palpable input lag to almost none, no Gsync required.

    That’s one reason I don’t understand all this excitement about Gsync. Then again, I don’t have a 144hz monitor, and 60fps isn’t that hard to achieve in most games. I just tweak my settings to achieve 60fps consistently. A locked frame rate always feels better to me anyway, with or without tearing.

    • That’s one reason I don’t understand all this excitement about Gsync.

      There are a lot of ways to solve tearing/stutters without GSYNC. However, several approaches entail lots of compromises (e.g. choosing to be being limited to 60Hz, or choosing to spend lots of money to get 120fps@120Hz). So some people prefer to at

      For a lot of us, there’s so much motion blur at 60Hz. Every single 60Hz LCD monitor have all failed the TestUFO Panning Map Readability Test — I dare you to try this test out :) — What this means is fine details are lost in motion blur during fast panning/strafing/turning in games. And 144Hz monitors have far less motion blur. All G-SYNC monitors are also bona-fide high refresh rate monitors, which have advantages into themselves.

      G-SYNC monitors includes an extra feature, called Ultra Low Motion Blur (ULMB) which is a motion blur reducing strobe backlight. It even works at 85Hz, much like an 85Hz CRT, if you find 120Hz too demanding for GPU. It’s the sequel to LightBoost, see happy comments from LightBoost users, as well as photos of 60Hz vs 120Hz vs LightBoost. Here, ULMB absolutely beautiful at 85fps@85Hz, or 100fps@100Hz, or 120fps@100Hz. Zero motion blur, zero stutters, zero tearing during VSYNC ON motion. Motion as clear as a CRT, where fast motion looks exactly as tack-sharp as stationary motion. But not all games can run at framerates that looks good enough for strobing (you ideally want framerate == stroberate for perfect motion, and you don’t want a stroberate too low to be flickery, like an old 60Hz CRT).

      And for those games that fluctuate in frame rate a lot, you just play GSYNC, and get the “always perfect VSYNC ON look at all frame rates”. Varying framerates that always looks like the display is always running at VSYNC ON, with the ability to run at Ultra details, without worrying about “dropping below a specific VSYNC ON refresh rate”. The freedom to play games with stutters, regardless of whatever game detail levels they use, is another allure of GSYNC, since 45fps GSYNC looks almost as beautiful as 60fps VSYNC ON, and 115fps GSYNC looks as beautiful as if the monitor was running a perfect 115fps@115Hz VSYNC ON. Framerate continually varies, with no visible stutters during framerate variances. GSYNC gives you the “permanent always-capped-out VSYNC ON look during variable frame rates”. Framerate suddenly falls from 60fps to 50fps? No problem; you don’t notice. It still looks like the frame rate is capped out. The only difference that occurs is a minor change from 16.7ms (1/60sec = 16.7ms) of motion blurring to 20ms of motion blurring (1/50sec = 20ms), which is actually an imperceptible difference; so you don’t notice the framerate varying from 60fps downwards to 50fps to 60fps. And since GSYNC supports up to 144Hz, you get the bonus of the impressive “wow” of low motion blur of high frame rates, but without worrying of slowdown artifacts anymore. As you can see, GSYNC eliminates the obnoxious visibility of slowdown issues, giving the permanent synchronized “capped out VSYNC ON” look despite varying frame rates.

      It kind of needs to be seen in person to be believed, but if it cannot be seen in person; A poor man’s interpolated simulation can be found in Blur Busters GSYNC Review Part #1 (view in a stutterfree browser, Chrome browser, Aero mode enabled, all windows primary monitor, and no other apps running, to make sure no stutters are injected into the GSYNC emulator animation). Unfortunately the animation does not do justice to GSYNC when the animation runs on a 60hz monitor, you need to see the animation on a non-GSYNC 120Hz monitor in order to understand the whole range of benefits a little better, but it gives you the rough idea of how framerate ramping up/ramping down can be done without injection of erratic stutters. As you can see, it’s hard to tell apart 30fps versus 35fps on GSYNC, and hard to tell apart 50fps versus 60fps on GSYNC, the differences between framerate is so subtle as it ramps up and down.

      That said, at the end of the day, if I am able to sustain 120fps@120Hz, I do prefer VSYNC ON framerate == stroberate == refreshrate, when using a strobe backlight. I’ve been playing solo games like Bioshock Infinite, using VSYNC ON, as I prefer the perfect motion clarity effect too, simultaneously with the CRT-like zero motion blur effect. I’m damn impressed at both NVIDIA ULMB (better-than-LightBoost seqeuel) and Turbo240 (bright, high contrast strobing found in EIZO’s FG2421, as an example). However, even my Geforce Titan is unable to sustain 120fps@120Hz in Crysis 3 (unless I obnoxiously reduce detail levels to boringness), and I really dislike motion blur of 60fps@60Hz, so in this case, GSYNC actually becomes a pleasant compromise for those certain GPU-killer games.

    • Yep. I gave them permission to reprint my article, with credit.

      Magazines can contact me for permission if they wish to reprint any of this site’s original articles. The wonderful folks at pcgameshardware liked this GSYNC test so much.

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