What does "Fast" Vsync do?

[Iggy Wolf]

I noticed that some games benefit from and are usually recommended to have Vsync in NVCP set to "Fast" Vsync. Under that option, Nvidia says that it's the equivalent of Vsync being off but still apparently somehow matching the FPS to the refresh rate and/or preventing FPS from going above refresh rate. I already have a Freesync/G-Sync monitor, so with G-Sync enabled, I'm not sure how much more it might benefit a game, but I have noticed that some games have reduced if not completely eliminated stutter when that option is set. Is there a better Vsync option that I'm supposed to use in conjunction with G-Sync?

[Boblin the Goblin]

It forces the monitor to only render completely rendered frames. It has increased input lag and turns the sync settings off since it's using the monitor directly.

It's better than adaptive sync at high frame rates and is generally recommended for games that have a higher FPS than the refresh rate of the monitor.

[Iggy Wolf]

Originally posted by SlowMango:

It forces the monitor to only render completely rendered frames. It has increased input lag and turns the sync settings off since it's using the monitor directly.

It's better than adaptive sync at high frame rates and is generally recommended for games that have a higher FPS than the refresh rate of the monitor.

Well, that's why I'm wondering how it plays with G-Sync. Since G-Sync is constantly syncing my refresh rate with my framerate, it'll never really go "above" the refresh rate unless it exceeds 165 Hz, which is my monitor's refresh rate. And I rarely have any game that can get the FPS to go THAT high.

Only older games like Half-Life 2 hit it, or newer games that aren't demanding like THPS 1 +2 Remake. That's why I'm wondering which option is considered the "best" to have set in unison with G-Sync. I rarely get tearing in games but I do get stutter in some of them, whether due to variances in FPS or bad frame times. And I'm wondering which Vsync option is the best to deal with bad frametimes.

[Nx Machina]

https://nvidia.custhelp.com/app/answers/detail/a_id/4161/~/if-i-have-a-g-sync-monitor,-should-i-enable-fast-sync-as-well%3F

[Satoru]

So V-sync is to render frames 'on tick' with your monitor's refresh rate which fixes tearing. Normal vsync has the problems of:

* you are capped at the monitor refresh rate on the high end
* Any tiny dips below the refresh rate causes vync to half your fps

G-sync is meant to address the second problem. That when you dip below the monitor's sync rate, your FPS doesn't collapse. It basically fixes tearing but allows your game to float FPS below the sync reate of your monitor without any issues. The issue with Gsync is that ABOVE teh refresh rate of your monitor you may experience tearing unless you turn on vsync.

Fast Vsync is really only useful if you're rendering the game at HIGHER than the refresh rate of your monitor. If you'r enot pushing basically 200fps then fast vsync doesn't help you in any way. Its to address the Gsync problem of when you go above the refresh rate of your monitor

Given that it sounds lke you're not hitting above the monitor refresh rate, then G-sync is fine for you. Note that I've seen a few games where Fast Vsync has caused weird problems so enabling it when you're not getting any practical benefits is probably not useful.

[Scheneighnay]

It's been a while since I've messed around with it, but from what I remember, don't.

Nvidia keeps a bunch of legacy settings on the control panel and I'm 50/50 on either fast vsync or some other vsync being one of those legacy settings which will just cause bugs on newer cards. It was years ago but I enabled one or the other and it broke a bunch of stuff until I figured out the cause.

Old fashioned vsync isn't even bad.

[ReBoot]

Originally posted by Iggy Wolf:

Originally posted by SlowMango:

It forces the monitor to only render completely rendered frames. It has increased input lag and turns the sync settings off since it's using the monitor directly.

It's better than adaptive sync at high frame rates and is generally recommended for games that have a higher FPS than the refresh rate of the monitor.

Well, that's why I'm wondering how it plays with G-Sync. Since G-Sync is constantly syncing my refresh rate with my framerate, it'll never really go "above" the refresh rate unless it exceeds 165 Hz, which is my monitor's refresh rate. And I rarely have any game that can get the FPS to go THAT high.

Only older games like Half-Life 2 hit it, or newer games that aren't demanding like THPS 1 +2 Remake. That's why I'm wondering which option is considered the "best" to have set in unison with G-Sync. I rarely get tearing in games but I do get stutter in some of them, whether due to variances in FPS or bad frame times. And I'm wondering which Vsync option is the best to deal with bad frametimes.

If your using G-Sync, keep V-sync on. Just the normal V-sync option, nothing else.

[Muppet among Puppets]

I think adaptive is the best.