Fast Sync problem?

notea · Aug 16, 2016

Hi,
I currently have a gtx 1070 and an LG Ultrawide monitor @75hz.. i have Fast Sync enabled but the FPS counter still shows 140-150 in BF4.. is this how its supposed to work? i thought the FPS counter should be locked at 75.. any ideas or help would be appreciated.. thanks

bigpinkdragon286 · Aug 16, 2016

NVIDIA graphics cards only support G-Sync, so you can't use Freesync. Standard VSync options are still available, however.

Hlsgsz · Aug 16, 2016

FreeSync only works on AMD cards, but you should keep it enabled regardless so your monitor goes from 60 to 75Hz. If you want to limit your FPS, you shoudl either usi a FPS limiter or, even simpler, go into NVidia control panel and enable adaptive Vsync for all apps or teh specific game(the latter preferably).

notea · Aug 16, 2016

bigpinkdragon286 :

My bad.. i meant Fast Sync.. Edited

Hlsgsz · Aug 16, 2016

Fast Sync and Vsync work differently. What you are seeing is normal behaviour and FS helps especially in that kind of situation(FPS way above the screens refresh rate). What you shoudl not be seeing, though, is tearing. And I'm guessing you are not seeing any

notea · Aug 16, 2016

Hlsgsz :

notea · Aug 16, 2016

Hlsgsz :

i know how v-sync works and i hate the added input lag thats why i never turn it on.. what im actually asking is if my RTSS FPS counter should display 75FPS or unlocked FPS (100-160 ish) when using Fast Sync

Hlsgsz · Aug 16, 2016

notea :

Unlocked. That's it's whole point. It doesn't lock framerate like Vsync.
Like i said, you are experiencing normal, expected behaviour.

notea · Aug 16, 2016

I read somewhere that for Fast Sync to work properly, i need to have FPS at least 2 or 3 times my monitor's refresh rate.. any ideas on this?

Hlsgsz · Aug 16, 2016

notea :

Yes that is correct. And your FPS is ok. Now, if you were only getting 80FPS, it wouldn;t have helped much.

notea · Aug 16, 2016

Hlsgsz :

i'm getting around 120 -160 FPS on BF4.. so that shouldn't be a problem with Fast Sync?

Hlsgsz · Aug 16, 2016

notea :

Hlsgsz :

i'm getting around 120 -160 FPS on BF4.. so that shouldn't be a problem with Fast Sync?

No, that sounds excellent. Are you experienceing any tearing?

notea · Aug 16, 2016

Hlsgsz :

notea :

No, that sounds excellent. Are you experienceing any tearing?

Not really, but some micro stutter here and there but not much and a lot more acceptable than using v-sync

Hlsgsz · Aug 16, 2016

notea :

Hlsgsz :

Not really, but some micro stutter here and there but not much and a lot more acceptable than using v-sync

Yeah fast sync doesn;t help with microstutter in itself. It only enables you a tearing free experience wihtout enabling Vsync, thus avoiding the stuttering Vsync brings to the table.
Anyway, no tearing means it's working

rdgoodri · Dec 31, 2016

Yeah thats currently my understanding as well, FPS will be up there, and unconstrained, but tearing will be eliminated.

notea · Jan 3, 2017

rdgoodri :

well, after few months with Fast Sync, i found that the Fast Sync limits your FPS to 2x your monitors' refresh rate, im using a 75 hz monitor and my FPS hovers around 140-150 ish, when i set it to 60hz, the FPS goes down to 120-130

bystander · Jan 3, 2017

Hlsgsz :

Fast Sync doesn't fix stuttering. That's actually one of its draw backs. It can create stuttering, where V-sync might not have any. But you are right in that Fast Sync does not lock your FPS at your refresh rate.

Here is an explanation of how it works:
Nvidia's drivers will create 2 back buffers regardless of what the game has for back buffers, as most games only have 1 back buffer. Nvidia will then treat those 2 back buffers similar to how triple buffering works, but with 1 key difference. Instead of resting idle if both back buffers are full with completed, but undisplayed images, Nvidia's Fast Sync will throw away the oldest image in the back buffers, and start rendering a new image. Normally, with DirectX, every image rendered has to be displayed, but with Fast Sync, they bypass that restriction, and will throw away the oldest image in the 2 back buffers, to allow it to keep rendering new images. When the display enters vertical blanking mode, the GPU will send it the most recent completed image, unlike normal, which sends the oldest completed image.

This is why your FPS counter continues beyond your refresh rate. The GPU is continuing to make images, even if they are not displayed. It is also why it can introduce stuttering, especially when you are only a little above your refresh rate, as you are skipping past some images, and not others. This can create uneven times between the rendered images, but displayed at an even interval.

Hlsgsz · Jan 4, 2017

bystander :

Hlsgsz :

Fast Sync doesn't fix stuttering. That's actually one of its draw backs. It can create stuttering, where V-sync might not have any. But you are right in that Fast Sync does not lock your FPS at your refresh rate.

Here is an explanation of how it works:
Nvidia's drivers will create 2 back buffers regardless of what the game has for back buffers, as most games only have 1 back buffer. Nvidia will then treat those 2 back buffers similar to how triple buffering works, but with 1 key difference. Instead of resting idle if both back buffers are full with completed, but undisplayed images, Nvidia's Fast Sync will throw away the oldest image in the back buffers, and start rendering a new image. Normally, with DirectX, every image rendered has to be displayed, but with Fast Sync, they bypass that restriction, and will throw away the oldest image in the 2 back buffers, to allow it to keep rendering new images. When the display enters vertical blanking mode, the GPU will send it the most recent completed image, unlike normal, which sends the oldest completed image.

This is why your FPS counter continues beyond your refresh rate. The GPU is continuing to make images, even if they are not displayed. It is also why it can introduce stuttering, especially when you are only a little above your refresh rate, as you are skipping past some images, and not others. This can create uneven times between the rendered images, but displayed at an even interval.

Correct. And hence it's limited usefulness to games which ones GPU can render and double the refresh rate or more.

bystander · Jan 4, 2017

The first paragraph was the only part aimed towards your statement. The rest was meant for the OP. This was the part I wanted to comment on "thus avoiding the stuttering Vsync brings to the table." Everything else you said was fine.

Fast Sync problem?

Distinguished

Splendid

Champion

Distinguished

Champion

Distinguished

Distinguished

Champion

Distinguished

Champion

Distinguished

Champion

Distinguished

Champion

Reputable

Distinguished

Champion

Champion

Champion

Share this page