NVIDIA G-SYNC: Variable Refresh Rate Monitors!

One small step closer to tomorrow’s Holodeck: NVIDIA G-SYNC! It is a technique for refreshing computer monitors at variable intervals (up to a certain limit). Instead of refreshing monitors at exact intervals, the monitor is refreshed when the GPU finishes generating a frame! [Image: AnandTech liveblog of launch event]

Variable refresh rates combines advantages of VSYNC ON (eliminate tearing) with the advantages of VSYNC OFF (low input lag), while virtually eliminating stutters (no mismatch between frame rate and refresh rate).

It is confirmed that this, alone, won’t eliminate motion blur as completely as strobe backlights (e.g. LightBoost), but this is a great step towards eliminating discrete refresh rates (which creates motion blur even at 144Hz. See photos of 60Hz vs 120Hz vs LightBoost), especially as the 144Hz limit is raised in the future, while using nVidia G-SYNC. Hopefully strobe backlight technologies can be combined with G-SYNC in the future — and hopefully already in some upcoming models.

EDIT:
– All G-SYNC monitors include an official strobe backlight mode, better than LightBoost!
– Mark Rejhon has quickly come up with a new method of dynamically blending PWM-free backlight at lower framerates to strobing at higher framerates; see addendum to Electronics Hacking: Creating a Strobe Backlight. This allows combining LightBoost + G-SYNC without creating flicker during lower framerates!

39 Comments For “NVIDIA G-SYNC: Variable Refresh Rate Monitors!”

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Mark Rejhon

It is wholly possible nVidia is already experimenting with combining strobe backlights (nVidia’s LightBoost, used in 3D Vision) along with nVidia G-Sync. According to the AnandTech liveblog:

10:04AM EDT – “Because of 3D vision we have a much deeper understanding of monitor technology and your visual systems”

10:52AM EDT – In normal mode, G-Sync monitors have to behave normally, in 3D mode they will flip into G-Sync mode

There may be visual problems with variable-rate strobing, however. One day, flicker-free 1000fps-capable variable refresh rate displays may eventually exist, and eliminate the need for strobe-based motion blur elimination.

Member

Lostconfused

On of Nvidia reps on a message board gave the following reply when asked about Lightboost/ToastyX

“We have a superior, low-persistence mode that should outperform that unofficial implementation, and importantly, it will be available on every G-SYNC monitor. Details will be available at a later date”