Question About GPU-Monitor Synchronization.

[Aviv]

Is there any differences between the GPU and the monitor refresh rate synchronization / display in this two cases (listed below) ?

* 'X' frames per second constant , V-sync OFF.

* 'X' frames per second constant ,V-sync ON .

I don't understand fully what V-sync does , does it synchronize the buffers out put in the vertical blanking interval in a different manner then V-sync off ?

Will V-sync on have less micro stutters or something along those lines ?

V-sync is just a buffer out put ceiling , or does it play a role is the actual image->refresh->buffer out put synchronization ?

Also , in case V-sync is turned off , is there any competitive benefit from capping the game max FPS into a number which is higher then you monitor refresh rate , lets say you have 144Hz monitor and you capped the game into 200 FPS max or higher ? (not super higher in order to prevent major screen tearing )

 

[Markkk]

V-Sync = Vertical Synchronization

The Refresh Rate of your Monitor most standard ones are 60Hz meaning they fully refresh the display 60 times per second
Newer monitors can are now 144hz - and likely to get even faster

3D TV's start at 200Hz up to 600Hz and require glasses to block the excess frames

A monitor with a refresh Rate of 144hz is only capable of displaying 144 FPS no matter how many frames you throw at it this fact remains a finite number of the design specs of the screen

Exceeding the specs of the Monitor by trying to push past this can cause screen jitter and tearing of the image as the monitor tries to best display the onslaught of data being pushed at it.

Turning on V-Sync slows down the FPS of the Card to match that of the monitor thus providing a usually better experience
- reducing screen tearing
- reducing screen Jitter
- reducing coil whine from gfx card (as it stops rendering hundreds of unseen frames)
- reducing power consumption of GFX Card
- reducing heat from GFX Card

Triple Buffering is what your thinking of it helps with quality of displayed images.

Limits of the human eye differ per individual, Some see jitter on higher refresh rates on so called jitter free high Hz TV's most will notice the Neon flicker of Neon lights or at least feel the difference of office lighting and not as comfortable as older bulbs

As these new Faster Monitors come into play there will be a lot more discussion and there will be a lot of Flaming about this is better as higher refresh rate blah blah blah etc its faster, you have to unlock your refresh you noob etc...

Limits of the Human Eye vary between individuals some find neon lighting fine other get headaches - This is the same with screens some see the refresh and its uncomfortable on the eyes and causes headaches and the feeling of nausea.
Some people can identify a 1/220th of a second image flashed on a screen others will never see that. The limits of the chemical reactions in your eye that see light differ per human also - there are a number of optical illusions that play on these limits - some see the effects other do not.

Just my 2c worth

 

[Aviv]

Thank man that is some great information right there

but can you address and answer some of the specific questions mentioned in the original post

because you have not answered to any

 

[Markkk]

OK lets say X frames say your card will crank out 500 FPS

Your Monitor is an HD (1920x1080p) @ 60Hz

With V Sync off - displays you will get X 500 fps but your screen will still only display 60 FPS
- you will likely get screen tearing

With V Sync turn on your gfx Card will slow to X 60 FPS and still only Display 60 FPS on the monitor
- Reduce Screen Tearing ... etc

V sync does not buffer any frames...

V Sync - does it best to match the actual refresh rate of the screen - which can reduce issues with display

Image quality buffering is related to the Buffering options in the setting listed as Single, Double, Triple - it uses the Vram (Video Ram) to produce better quality Images

With V-Sync Turn OFF - X Frames exceed the monitors refresh limit and the Monitor Still only displays the 60 FPS
Some will same there is no point having this on/off it makes zero difference

But in Fast Action Games you may exceed 60 FPS in a single turn - ie spinning the camera like a crazy person and faster FPS generation can improve the Frame Render at that point in the turn say a spin which could look better with 500 Fps rendered as apposed to only 60 Frames rendered - and thus appears to turn smoother (even thought the Monitor is limited to displaying 60 FPS) those extra frames displayed in the turn may provide a slightly smoother turn

Some may not notice this other may notice this effect. Again it may introduce screen tear and Jitter which some will live with and other find more distracting.

It does not Buffer these extra Frames the Monitor can only display 60 Frames So the other 440 Frames are lost and not displayed

Does this explain it better?

 

[Aviv]

So simply a constant 30 FPS motion on a 60Hz screen with V-sync off will not differ in any manner then a constant 30 FPS motion on a 60Hz screen with V-sync on ?

Therefore V-sync only comes into play in the display modification when the GPU tries to put in more frames then the monitor can refresh ?

 

[Markkk]

Correct

The screen will still be refreshing at 60 FPS - even though the updated images are at 30 fps

 

[test090927]

http://images.eurogamer.net/2013/articles//a/1/6/2/5/7/2/2/Nvidia1.jpg.jpg
http://images.eurogamer.net/2013/articles//a/1/6/2/5/7/2/2/Nvidia2.jpg.jpg
http://images.eurogamer.net/2013/articles//a/1/6/2/5/7/2/2/Nvidia3.jpg.jpg
http://images.eurogamer.net/2013/articles//a/1/6/2/5/7/2/2/Nvidia4.jpg.jpg
http://images.eurogamer.net/2013/articles//a/1/6/2/5/7/2/2/Nvidia5.jpg.jpg

From http://www.eurogamer.net/

 

[Aviv]

Markk you are wrong on this one , V-sync off will have tearing even in the monitor refresh rate , even if you get 60 FPS and your monitor refresh rate is 60Hz with V-sync off you refresh wont be synchronized with your GPU .

 

[Markkk]

You 'can' experience screen tearing on any LED/LCD monitors

You 'usually' notice it most when you 'exceed' Frames - but can also happen when you don't have enough frames, it does "vary greatly between brands."

Here is some more information: http://en.wikipedia.org/wiki/Screen_tearing

Turning On V-sync and Enabling Triple Buffering Usually stops screen tearing in it's tracks

'Most' people are overclocking there Video Cards and then run into this issues as in order to see correctly how many FPS V-sync needs to be turned off - then they start complaining about screen tearing

As those pictures show and briefly describe the Fault

If you Don't have enough Frames you get Stuttering (sometimes tearing) a form of input lag as described in the article, and your pics

Simply experiment with V-Sync, Triple Buffering and Refresh Rate if you are experience any of these issues, these are the main settings to adjust in resolving whatever display Tear/Judder/Lag/Potatoes/Blah/Meh issues you suffer from.