Question about input lag with VRR on a high RR monitor with a low fps game.

[Dooberknob]

The way I understand it, monitors will have the least input lag when displayed at their maximum refresh rate. I've seen tests that show very high performance 360hz monitors perform poorly when used at 60hz.

So say for example you're playing a game on a 360hz monitor that is locked to 60fps with Gsync/Freesync on. Since the refresh rate rate is now going to be around 60hz to match the fps, would this add lag, or does VRR have some way of keeping the high refresh performance at low refresh rates? Would it be better to turn VRR off and use Vsync instead in this scenario if you're having problems with tearing?

Thanks.

[jorimt]

The way I understand it, monitors will have the least input lag when displayed at their maximum refresh rate. I've seen tests that show very high performance 360hz monitors perform poorly when used at 60hz.

The issue you're referencing only applies to 360Hz monitors forced to a physical 60Hz refresh rate, as most 240Hz+ monitors do scanout rate conversion to try and fit and/or stretch a 60Hz signal to the higher native max refresh rate of the display, creating additional delay. This scenario is really only relevant if you're considering the monitor for a game console that is limited to 60Hz.

Scanout rate conversion does not apply to 360Hz VRR at 60 FPS, which would actually have faster frame delivery than 60 FPS on a native 60Hz display due to the increase in scanout speed (16.6ms vs 2.8ms).

[Dooberknob]

The issue you're referencing only applies to 360Hz monitors forced to a physical 60Hz refresh rate, as most 240Hz+ monitors do scanout rate conversion to try and fit and/or stretch a 60Hz signal to the higher native max refresh rate of the display, creating additional delay. This scenario is really only relevant if you're considering the monitor for a game console that is limited to 60Hz.

Scanout rate conversion does not apply to 360Hz VRR at 60 FPS, which would actually have faster frame delivery than 60 FPS on a native 60Hz display due to the increase in scanout speed (16.6ms vs 2.8ms).

OK, so if I'm understanding this correctly, the scanout rate of the monitor does not change when the monitor is displaying lower refresh rates due to VRR+lower fps. As in the previous example playing a 60fps locked game on a 360Hz monitor with VRR on, I'm still getting the same 2.8ms scanout rate as I would be playing at 360Hz without VRR. I take it the behavior is the same both Freesync and Gsync? The extra lag would only be an issue for example if I plugged a PS4 into the 360Hz monitor, which is locked at 60Hz with no VRR.

[RealNC]

OK, so if I'm understanding this correctly, the scanout rate of the monitor does not change when the monitor is displaying lower refresh rates due to VRR+lower fps. As in the previous example playing a 60fps locked game on a 360Hz monitor with VRR on, I'm still getting the same 2.8ms scanout rate as I would be playing at 360Hz without VRR.

Yes. Each frame is completely scanned out in 2.8ms. Then the monitor waits for 13.9ms doing nothing. At 60Hz, the monitor scans out each frame in 16.7ms and there is no waiting at the end. The result is that at 360Hz, you can already see the whole frame by the time 60Hz would have barely finished displaying a little bit of it at the top. So you see each frame faster, thus there's less button to pixel lag.

I take it the behavior is the same both Freesync and Gsync?

Yes.

The extra lag would only be an issue for example if I plugged a PS4 into the 360Hz monitor, which is locked at 60Hz with no VRR.

Yes.

[jorimt]

Yes, what RealNC said ^

[Dooberknob]

Awesome. Thanks guys.