Gsync and Vsync

[namarino]

So I posted a question about this the other day but I wanted to get some clarification. Vsync essentially limits the power of your GPU by limiting the number of frames it can output to the refresh rate of the monitor. I get that. If Vsync is off and your fps goes over the refresh rate, you get screen tearing. If Vsync is on, you get mouse lag. I tested both of these and I can see them, although the lag is difficult to detect. But my question is this. What happens if you have a 144Hz refresh rate and are playing a game that your GPU can't output more than 144 fps with? What what happens if you just keeps Vsync off? And what would happen if you turn Vsync on? Someone suggested that Vsync would cap your framerate at 75 or something. I figured that so long as you don't exceed your monitor's refresh rate, you could keep Vsync off so as to avoid the lag and the screen tearing. Maybe I'm wrong though. Thanks for the help. It is much appreciated.

[JebKerman]

Vsync limits GPU (effectively caps the framerate) if you can't reach the max refresh rate of your monitor just leave it off

Gsync "limits" monitor (in a good way) It matches the monitors refresh rate to that of the GPU, and caps the GPU like Vsync if it exceeds it, just a bit more smoothly iirc.

[Glenwing]

So I posted a question about this the other day but I wanted to get some clarification. Vsync essentially limits the power of your GPU by limiting the number of frames it can output to the refresh rate of the monitor. I get that. If Vsync is off and your fps goes over the refresh rate, you get screen tearing. If Vsync is on, you get mouse lag. I tested both of these and I can see them, although the lag is difficult to detect. But my question is this. What happens if you have a 144Hz refresh rate and are playing a game that your GPU can't output more than 144 fps with? What what happens if you just keeps Vsync off? And what would happen if you turn Vsync on? Someone suggested that Vsync would cap your framerate at 75 or something. I figured that so long as you don't exceed your monitor's refresh rate, you could keep Vsync off so as to avoid the lag and the screen tearing. Maybe I'm wrong though. Thanks for the help. It is much appreciated.

 

V-Sync will limit your GPU's output to 144fps. If you can't maintain 144fps, it will immediately drop to 72fps (sending the same frame twice until your GPU starts generating frames fast enough for 144fps again), and if you drop below that it will go down to 36fps. etc. This can create stuttering if your framerate varies a lot, as it will rapidly switch between 144fps and 72fps if your framerate hovers around the 144fps mark.

 

You can get tearing at any framerate if the GPU and display are not synchronized, it's not just when your framerate goes above the monitor's refresh rate. It just happens more often when you're above.

[namarino]

V-Sync will limit your GPU's output to 144fps. If you can't maintain 144fps, it will immediately drop to 72fps (sending the same frame twice until your GPU starts generating frames fast enough for 144fps again), and if you drop below that it will go down to 36fps. etc. This can create stuttering if your framerate varies a lot, as it will rapidly switch between 144fps and 72fps if your framerate hovers around the 144fps mark.

 

You can get tearing at any framerate if the GPU and display are not synchronized, it's not just when your framerate goes above the monitor's refresh rate. It just happens more often when you're above.

How noticeable is it though? It seems like at 144hz, it's better to leave Vsync off at that point. So if I leave it on, is the screen tearing really all that noticeable below the refresh rate?

[Glenwing]

How noticeable is it though? It seems like at 144hz, it's better to leave Vsync off at that point. So if I leave it on, is the screen tearing really all that noticeable below the refresh rate?

 

That's really up to the individual to decide.

[namarino]

That's really up to the individual to decide.

Do you have any experience with it? If so, was it noticeable?

[Glenwing]

Do you have any experience with it? If so, was it noticeable?

 

I don't often notice tearing in general except during cutscenes, whether I'm above or below the refresh frequency of my monitor. But like I said, it depends on the individual.

[namarino]

I don't often notice tearing in general except during cutscenes, whether I'm above or below the refresh frequency of my monitor. But like I said, it depends on the individual.

I just read about something called adaptive vsync. Do you know anything about that? 

[Glenwing]

I just read about something called adaptive vsync. Do you know anything about that? 

 

Yes, it basically turns off V-Sync whenever you drop below 144fps (or whatever your monitor's frequency is), but keeps it on when you're above 144.

[DXMember]

This one's pretty much a wall of text, but it's a beautiful piece of literature with excellent examples and easy to understand terminology:

http://hardforum.com/showthread.php?t=928593

 

I suggest you read the entire article,

 

but long story short - Vsync On - when your GPU finished a frame it waith for your monitor to be 'ready' your monitor is ready only at precise moments in time defined by your monitors refresh rate. If your GPU has a frame for every time the monitor is 'ready' then you get FPS that is of your max refresh rate,

if your GPU doesn't have a frame ready when your monitor is ready, then the monitor takes the previous frame - thus introducing delay which means that what you see on screen at this moment has happened in previous frame and is no longer true

 

The reason Mouse cursor laggs is because most of the times game engine is strictly linked to the frame rate and does all calculation (including Mouse movement) once a frame. Some games (World of Warcraft for example) give you an option to enable Hardware cursor which helps with that.

 

The linked article explains it much better and in a greater detail, I suggest you read it.

Also they predicted Adaptive Refresh Technologies 10 years ago

[namarino]

This one's pretty much a wall of text, but it's a beautiful piece of literature with excellent examples and easy to understand terminology:

http://hardforum.com/showthread.php?t=928593

 

I suggest you read the entire article,

 

but long story short - Vsync On - when your GPU finished a frame it waith for your monitor to be 'ready' your monitor is ready only at precise moments in time defined by your monitors refresh rate. If your GPU has a frame for every time the monitor is 'ready' then you get FPS that is of your max refresh rate,

if your GPU doesn't have a frame ready when your monitor is ready, then the monitor takes the previous frame - thus introducing delay which means that what you see on screen at this moment has happened in previous frame and is no longer true

 

The reason Mouse cursor laggs is because most of the times game engine is strictly linked to the frame rate and does all calculation (including Mouse movement) once a frame. Some games (World of Warcraft for example) give you an option to enable Hardware cursor which helps with that.

 

The linked article explains it much better and in a greater detail, I suggest you read it.

Also they predicted Adaptive Refresh Technologies 10 years ago

Wow that was really good! The only thing that I've never experienced though is this whole thing about Vsync capping the framerate at set values below your refresh rate. I was playing a game just yesterday and I had Vsync on and the framerate was hovering just around 53 fps. Is that because adaptive Vsync is now being used? Adaptive vsync sounds like the best of both world to me.

[DXMember]

Wow that was really good! The only thing that I've never experienced though is this whole thing about Vsync capping the framerate at set values below your refresh rate. I was playing a game just yesterday and I had Vsync on and the framerate was hovering just around 53 fps. Is that because adaptive Vsync is now being used? Adaptive vsync sounds like the best of both world to me.

Yes it is most likely Adaptive VSync in use or a Tripple buffering