What is Vsync in gaming?

[adampcpower]

Im currently using a very crappy lcd monitor with 60hz refresh rate through a VGA cable (waiting for my new monitor), and when i played Deus Ex: Human revolution with my ZOTAC Geforce gtx 670 AMP! edition and turned "Vsync" off, i was getting like 1250, in the thousands, compared to 60fps with it on. also, i heard a sort of whining from my graphics card when i had it on and the game screen started to flicker and studder. what is vsync and is it bad for my gpu/computer if i turn it off?

 

[akxpckwb]

Vsync basically synchronizes your frames per second with your monitor refresh rate. It is not bad for any component and can reduce tearing in some instances. The problem is that it reduces your FPS rate if it is higher than your refresh rate

 

[kulmnar]

Im currently using a very crappy lcd monitor with 60hz refresh rate through a VGA cable (waiting for my new monitor), and when i played Deus Ex: Human revolution with my ZOTAC Geforce gtx 670 AMP! edition and turned "Vsync" off, i was getting like 1250, in the thousands, compared to 60fps with it on. also, i heard a sort of whining from my graphics card when i had it on and the game screen started to flicker and studder. what is vsync and is it bad for my gpu/computer if i turn it off?

If the monitor refresh rate is at 60hz, the maximum fps you are going to see with your eyes is 60fps, even if the card is outputting 120fps or 1200fps (lol!). If you have a good video card, leave vsync on for a much smoother gaming experience and to avoid wasting power because with vsync off, your card will run at maximum speed and try to output as many frames per second as possible. In a 60hz monitor, the most you will see is 60fps therefore there is no point in having your card struggle to output hundreds or thousands of frames per second.

 

[fiduke]

Basically, Vsync matches up frames to your refresh rate. In your case, your monitor can show only 60FPS, so that is all you will ever get. It doesn't matter if your card can do 1 million FPS, you'll only ever see 60. Keeping Vsync on will produce the smoothest gameplay in this case.

However lets say you're getting 43 FPS in a game and you have Vsync on. This can cause the game to look less smooth because of the way frames are rendered with Vsync.

Simple solution: Getting over 60 FPS on your monitor? Keep Vsync on. Getting less than 60 FPS? Turn Vsync off. The 670 actually even comes with something called adaptive Vsync which does this automatically, on the fly, for the smoothest framerates possible. From what I understand Nvidia is still working out the kinks, but it's definitely an amazing feature. It'll have the most relevance on higher resolution 120hz monitors.

 

[djscribbles]

Everything these guys are saying is correct. In most cases, I would say leave vsync on, however the odd whining and stuttering you are seeing is strange, I don't know what to think of that...

I would try turning on vsync and restarting the game, just to make sure it wasn't a weird behavior by the game. Vsync off will typically make your GPU run quite a bit hotter than it needs to, so it's better to have it on if you are clobbering the games requirements.

 

[adampcpower]

Everything these guys are saying is correct. In most cases, I would say leave vsync on, however the odd whining and stuttering you are seeing is strange, I don't know what to think of that...

I would try turning on vsync and restarting the game, just to make sure it wasn't a weird behavior by the game. Vsync off will typically make your GPU run quite a bit hotter than it needs to, so it's better to have it on if you are clobbering the games requirements.

do you think the whining from the GPU is an issue? in the pause menus i was getting above 5,000 fps! i instantly turned vsync back on because i was worried my gpu was going to get damaged.

also, the stuttering image on the monitor i believe is because of the very low quality of VGA cable i was using. i saw it less severely in other games that required some gpu power

 

[djscribbles]

There are two potential sources for the whining you hear:
1: The fan at a certain RPM is noisy
2: At certain power levels, an inductor coil in your PC begins to resonate and makes a high pitched 'electrical' whine

In either case, these things are not directly harmful to your card; if it's the fan, just make sure you keep an eye out for it failing.

Just because I'm not 100% sure I'm reading you correctly, the whining is occurring when vsync is ON and your FPS is at 60 (which is what I think you are saying). I would normally expect the opposite, where your GPU runs at 100% giving you insane FPS and putting the fans on full speed, creating a whining noise from the fans at high rpm.

 

[adampcpower]

There are two potential sources for the whining you hear:
1: The fan at a certain RPM is noisy
2: At certain power levels, an inductor coil in your PC begins to resonate and makes a high pitched 'electrical' whine

In either case, these things are not directly harmful to your card; if it's the fan, just make sure you keep an eye out for it failing.

Just because I'm not 100% sure I'm reading you correctly, the whining is occurring when vsync is ON and your FPS is at 60 (which is what I think you are saying). I would normally expect the opposite, where your GPU runs at 100% giving you insane FPS and putting the fans on full speed, creating a whining noise from the fans at high rpm.

no, it happens when the Vsync is OFF and the GPU is doing 100% load. i'm trying to diagnose where the high pitch whining is coming from as im sure it is definitely not from the fan speed increase. i think it would be safe just to keep it on though 😀

 

[djscribbles]

If it is not the fan, then it is coil whine (which is the same noise you can sometimes hear monitors/TVs making), as there are no other moving parts. Coil whine is basically caused by inductors, which are coils of wire which electricity passes through, the coil shape causes changes in the voltage to be magnetically dampened (much like a shock in a car), these are often used in power supplies to smooth AC voltage into DC voltage.
However, the coil also experiences some physical force, and if they are a little loose, they can make a high pitched whining noise as they vibrate in place at certain power levels.

It's completely harmless, and it's more likely that the noise is coming from your power supply, but only when your GPU is really using a lot of power. If you want to be cautious, you can double check that your PSU 12V current source is sufficient for your GPU at max load, however coil whine can really vary wildly along different load levels (sometimes you will see it at low load levels, sometimes high, or medium).