Strobing and VSYNC

Ask about motion blur reduction in gaming monitors. Includes ULMB (Ultra Low Motion Blur), NVIDIA LightBoost, ASUS ELMB, BenQ/Zowie DyAc, Turbo240, ToastyX Strobelight, etc.
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knypol
Posts: 59
Joined: 18 Aug 2016, 03:40

Strobing and VSYNC

Post by knypol » 25 Aug 2016, 06:43

Hello,

Should I use VSYNC when in strobing mode for best motion quality? I've noticed that when my game cant reach (fps to low) my refresh rate strobing is basically useless - it looks even worse than without strobing. When my fps are more than refresh rate it looks ok but not sure if its better with vsync on or off. Page http://www.testufo.com/#test=framerates is always syncing with refresh rate and looks great. Can I somehow launch those test without refresh sync so I can check if VSYNC is better when fps are grater than monitor refresh? Or maybe there is some other application with moving text that doesnt sync fps with refresh?

Best regards
knypol

Vega
Posts: 191
Joined: 18 Dec 2013, 21:33

Re: Strobing and VSYNC

Post by Vega » 14 Sep 2016, 19:56

When using a strobing backlight, the FPS must be at or above the set refresh rate of the monitor to look proper. This generally means you need way more GPU power than you would need for G-Sync mode, as it's the minimum FPS that counts while strobing.

You also need V-Sync = ON to prevent screen tear. You will get some input lag with V-Sync = ON. The way around that is to set your FPS to one lower than refresh rate. I know that slightly violates the rule above, but it's the best overall combination I find.

An example: 144 Hz refresh rate with strobing backlight. I set FPS cap to 143 and V-Sync = ON. This gives me no screen tear, elminates most V-Sync input lag. This only downside is that once per second, you will get a double frame. At 144 Hz the double frame isn't really that noticeable, I'd rather have that then the increase in input lag.

Fast-Sync would have eliminated this problem, but NVIDIA in their infinite wisdom made Fastsync not work with SLI. Basically you need SLI to keep FPS in most modern games above 144, but it only works single GPU which generally isn't fast enough. I guess you could run it with older games. It's basically a catch 22.

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