V-Sync or FPS Limiter?

[AstroBenny]

So I understand that if you enable V-SYNC (locked at 60fps), the GPU won't place/switch the frame in the primary frame buffer to be displayed on the monitor (60Hz) until all of that frame has been rendered.

But how is that different from having a locked fps at 60? One frame is switched/sent to the primary frame buffer, displayed, and the next frame is being rendered in the secondary frame buffer and all of the frame is rendered due to a consistent locked 60fps and then that frame is shown with the next monitor refresh, meaning screen tearing is removed. Why is this not the case..?

Source of my misunderstanding:

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

[MoonKnightSpidey]

I would also like to know. Good question. @Minibois or some mod will answer in a few seconds.

[PlayStation 2]

V-Sync is V-Sync.

An FPS lock simply tells the game to try not to render above 60fps. It doesn't need to wait for the monitor to draw the frames.

[don_svetlio]

fps limiter since V-sync enforces a slight FPS penalty and it can only limit to the refresh rate or halves of it - say if you have a 60Hz screen and dip to 49fps, V-sync will allow for only 30fps to be displayed at once

[AstroBenny]

@GoodBytes

[Enderman]

im fairly sure that vsync is the exact same thing as an fps lock, its just locked to the refresh rate of your monitor, which is why you cna set an fps lock to any fps but vsync only to your actual refresh rate

 

when you lock fps, it only render a frame that many times per second, instead of doing as many as it can

when you lock fps to the monitors refresh rate, then the monitor only gets that many frames, which eliminates tearing because the framerate matches the refresh rate

 

also with vsync, if your fps drops below 60 it will change the limit to 30fps, so that your monitor still has no tearing and just duplicates frames (because it only gets 30fps and it has 60Hz)

 

with a frame limiter, it will only lock the fps to that framerate, and if it drops below that you will get tearing, but not the stuttering you would get when vsync drops you to 30fps

[Guest Kloaked]

It's the way V-Sync forces frames to be displayed, contrary to just a frame rate limiter which doesn't do anything but cap your FPS. V-Sync does more than that but I can't actually explain it without sounding like I'm trying too hard to understand, because I don't actually understand it myself.

 

But basically V-Sync isn't the same thing as a frame rate limiter.

[AstroBenny]

im fairly sure that vsync is the exact same thing as an fps lock, its just locked to the refresh rate of your monitor, which is why you cna set an fps lock to any fps but vsync only to your actual refresh rate

 

when you lock fps, it only render a frame that many times per second, instead of doing as many as it can

when you lock fps to the monitors refresh rate, then the monitor only gets that many frames, which eliminates tearing because the framerate matches the refresh rate

This says otherwise

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

[Enderman]

This says otherwise

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

i added a bit to the end of my post

that's the difference that is talked about in your link

 

the only difference is how it behaves when you drop below 60fps

[minibois]

So I understand that if you enable V-SYNC (locked at 60fps), the GPU won't place/switch the frame in the primary frame buffer to be displayed on the monitor (60Hz) until all of that frame has been rendered.

But how is that different from having a locked fps at 60? One frame is switched/sent to the primary frame buffer, displayed, and the next frame is being rendered in the secondary frame buffer and all of the frame is rendered due to a consistent locked 60fps and then that frame is shown with the next monitor refresh, meaning screen tearing is removed. Why is this not the case..?

Source of my misunderstanding:

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

Well locked is not the same as capped. Locked = doesn't move from that fps number and capped means it doesn't go over that fps number.

Vsync is a cap, as in the fps will not go higher than the monitor refresh rate. A lock inside a game engine will just set up the updating of the game to for example 60 times per second, meaning it would also only have to update the screen 60 times per second. From my understanding vsync does delay frames to keep the fps under the Hz, meaning it will add a tiny bit of delay even.

[MEC-777]

Vsync and fps limit/target are NOT the same thing. You can and will still get screen/image tearing with frame limit on 60fps but Vsync off. Vsync is what synchronizes the frame output from the GPU to match that of the refresh rate of the display. 

 

With Vsync off and frame limit on, the GPU is being limited to produce 60fps, but the timing at which the GPU pushes the frame to the display can still be out of sync with the refresh rate of the display. Vsync is better for smoothness, and Vsync + frame limiter is better for reduced input lag since it's not throwing away X number of frames between each refresh as it does with just Vsync enabled. 

 

 

Clear as mud?

[AstroBenny]

Vsync and fps limit/target are NOT the same thing. You can and will still get screen/image tearing with frame limit on 60fps but Vsync off. Vsync is what synchronizes the frame output from the GPU to match that of the refresh rate of the display. 

 

With Vsync off and frame limit on, the GPU is being limited to produce 60fps, but the timing at which the GPU pushes the frame to the display can still be out of sync with the refresh rate of the display. Vsync is better for smoothness, and Vsync + frame limiter is better for reduced input lag since it's not throwing away X number of frames between each refresh as it does with just Vsync enabled. 

 

 

Clear as mud?

But exactly 60fps locked at 60Hz would be in sync anyway surely...?

[MEC-777]

But exactly 60fps locked at 60Hz would be in sync anyway surely...?

 

No, not necessarily. The frame timings can be off/out of sync with the refresh of the display which can cause image/screen tearing. Vsync synchronizes frame timings with the refresh rate.

[AstroBenny]

i added a bit to the end of my post

that's the difference that is talked about in your link

 

the only difference is how it behaves when you drop below 60fps

On a sidenote:

In the link it says "Double-buffering is a technique that mitigates the tearing problem somewhat, but not entirely"

Is this implying that single buffering is actually a thing in computer graphics/gaming? I thought there was only double/triple buffering..

[Guest]

Essentially, what tearing is, is anytime the screen is displaying more than 1 frame at the same time. Think of 1 half of the screen displaying one frame, and the bottom half of the screen displaying another, that's basically what video tearing is. This can happen whenever the gpu sends frames to the monitor in between the monitor's refreshes.

 

Now the only way to completely eliminate tearing is to ensure that the screen is only ever displaying ONE frame at a time. This can be done in a few ways:

 

1. Vsync, which forces the gpu to wait on the monitor, only sending a frame to the monitor each time it refreshes ensuring that the monitor is only displaying 1 frame at a time.

 

2. gsync/free sync. basically takes the opposite approach. Instead of the gpu being a slave to the monitor's refreshes, the display is a slave to the gpu and dynamically refreshes as it receives frames from the gpu.

 

 

Now as far as FPS limiting goes, limiting FPS by itself does absolutely nothing to combat tearing. If you cap your fps at 60 and have a 60 hz display, there's absolutely nothing stopping the gpu from sending frames to the display in between the displays refreshes, causing tearing. Even if your fps is far below your monitor's refresh rate, you'll still get tearing.

 

Framerate being limited is just a side affect of vsync (since the gpu can only send a frame for each monitor refresh with vsync enabled, there would be no way for your framerate to be above the monitor's refresh rate). Framelate limiting in itself doesn't have anything to do with vsync.