Rip Gsync (FastSync?)

[geordiejc]

Is this RIP Gsync?

/me waves goodbye to his resale value of 4k gsync

It's not as responsive as vsync off in terms of input lag, but very close and no screen tearing ? - any info on this vs gsync?

 

[geordiejc]

They claim it reduces input within ~10ms of vsync off but you get no tearing which is a win win!

My question is how does the input latency compare to gsync input latency. Gsync will limit your FPS to the max refresh rate of your monitor, in my case 60.

 

[geordiejc]

Its not the same as Gsync at all though...

It will work at the monitor refresh rate eg. 60hz, 144hz or whatever it is....

And your FPS will have to be higher than the monitor refresh rate...

Gsync will sync the monitor to whatever your FPS is from 30-144hz with no tearing or lag.

But yes fast sync looks good if you play CS:GO or something at 300fps and want no tearing or lag, or it might still be better to run at 300fps Vsync off for the lowest possible lag.

But not a replacement for Gsync at all.

I agree with some of what you say. I play cs:go at 60fps/hz gsync. with fast sync you can get 240fps in 4k WITHOUT screen tearing which is essentially what gsync does.

Gsync solved the problem of screen tearing with vsync off and input lag with vsync on. In summary i think the only difference is fast sync wont limit your FPS but will give the same result as gsync.

 

[geordiejc]

ffs it's a sink body and go faster strips. Can't get the staff these days ...

 

[geordiejc]

From what I read it replaces gsync

I've just been watching this video and the guy explains that fastsync is best used when the render rate is above the refresh rate and gsync is best used when the render rate is below the refresh rate. at the 9min 30 mark.

I still think this could be the end of gsync though!

The thing is .... i have tested cs:go limited to 59fps on my 4k gsync with gsync off and vsync off but the game limited to 59 fps and it isnt anywhere near as smooth as gsync on. This is where gsync comes in i believe.

 

[geordiejc]

Tom peterson said specifically do NOT use fastsync if its above 60fps on a 60hz monitor. So i dunno where people are getting that you need to drive your fps up past what your monitor can do. He said its good for when its under 60fps but not at or over 60. He said this on pcper stream the other day.

Why not if you want to prevent screen tearing and input lag on a 60hz monitor? e.g. i want to play cs:go at 300fps on a 60hz monitor without screen tearing? why not use fastsync as this eliminates screen tearing and the negative impacts of input latency when using vsync?

 

[geordiejc]

This doesn't replace GSync. FastSync is used to eliminate screen tearing in situations where the game's framerate is far greater than the monitor's refresh rate, but without the input lag of VSync. The feature is built into the card and does not require a monitor with special hardware. Unlike Gsync, you cannot use FastSync in situations where the framerate dips below the refresh rate, as that will only lead to stuttering, just like Vsync.

No. No, you are not allowed to do that.

Ah so.... fastsync can't work when render rate is below refresh rate as this causes stuttering, which gsync resolves.

 

[geordiejc]

I'm pretty confused so let's all work through an example and see if we can get to the bottom of this (even if its just for my benefit!)

Problem:

If i enable Gsync, my GPU + Monitor are in sync and the GPU renders 60FPS MAX - it doesnt render anything above - so how can fastsync and gsync work together when gsync won't let the GPU render > 60fps.

 

[geordiejc]

GSYNC ceases to function at 60FPS (monitor cap) and VSYNC functionality kicks in IF enabled (which it is by default, there is an option in NVCP). You can just turn this off so once you exceed your refresh rate it runs VSYNC off.
If you turn FASTSYNC on then its like VSYNC off so you can exceed your refresh rate and then you will get the VSYNC benefits (no tearing) but without the associated input lag.
GSYNC users have tried to get around this problem previously by capping their framerate below their monitor refresh rate but this has its own problems.

To be clear, G-SYNC is STILL preferable to no G-SYNC if you get low frame rates (below refresh rate) but as we already know, G-SYNC is useless if you are always at maximum refresh rate, and this is where FASTSYNC comes in. Hence why some may find that they are useful together.

So should i set this to vsync off? - i use gsync.

 

[geordiejc]

Solve me this as linus the ball bag couldn't:

On a 144hz Gsync monitor;

At 144 hz Gysnc on + Vsync on = lowest input lag.
At 45 hz Gsync on + Vsync off = lowest input lag.

Why?









Source:

 

[geordiejc]

Because Linus is an idiot.
In the video he talks about turning vsync on and off in-game. With gsync you ALWAYS have vsync off in game, you then use control panel to control gsync's vsync behaviour. If he was turning it on/off in game and not doing anything in control panel, we cant be sure what settings he was actually using.

The other thing is that nvidia have updated their drivers as to how gsync's "vsync" behaviour works, so even if he did the testing right (which based on his video he didnt), the results would now be different anyway.

At 45fps vsync would be having no effect, its purely Gsync working (unless he turned on vsync in game which would revert to traditional vsync and gsync wouldnt be operational)

So you should always use gsync with vsync on in NVCP and the ingame vsync settings don't matter because NVCP has priority over ingame?

 

[geordiejc]

Thanks for all replies so far. Why would vsync off in game be relevant if the NVCP vsync on overrides this ?

 

[geordiejc]

I don't know if it does but the last time I had stuttering, I scratched my head for a bit, checked the game settings and V-Sync was on in game and turning it off fixed it. Not sure if the newer drivers have more control but possibly. probably best just to make sure V-Sync is off in game settings but on in the NCP.

Kind of a conflict of interest, each trying to override each other perhaps?

 

[geordiejc]

I had direct confirmation from Nvidia engineers earlier this year that G-SYNC does nothing special whatsoever to 'cap frame rates'. It simply reverts to VSync on if the framerate exceeds the refresh rate cap and VSync is enabled in NVCP or otherwise. The reason you're not seeing any confirmation otherwise is because the 'traditional behaviour' still applies here.

Yeah vsync on is how it was always meant to be - im really inrterested to see how effective fastsync is compared with gsync.