Free sync vs. G-sync

[Marcus Torre DeProspero]

What is the real difference and how does it effect gameplay. Doesn't it work on both GPUs? Will I be able to reach 144hz on a Free sync monitor with an Nvidia GPU?

[Samfisher]

Freesync and G-Sync are optional tech.  You can use any GPU with any monitor that supports either tech, you just won't be able to use Freesync/G-sync.  It will act as a regular monitor.

[CapricaBuccaneers]

This is a particularly good article for a general comparison of the two from TFTCentral: 

 

http://www.tftcentral.co.uk/articles/variable_refresh.htm

 

[Lotus]

They both work similarly: adaptive refresh rate down to a certain point (monitor dependent) below the monitor's refresh rate (like 60-144hz), but then VSync once you hit your monitor's refresh rate. Since current DX11 implementation of VSync isn't proper VSync but a render queue (a queue of frames is kept and the next one has to wait for the monitor's refresh), this results in tons of input lag. Since GSync/Freesync  IS Vsync at above your monitor's refresh rate, these adaptive sync technologies ALSO result in massive input lag if the framerate is high enough. Basically, in any use case I would have for them, I would turn it off and leave it unused. Until they fix VSync's input lag problem, I will not use GSync or Freesync, and I don't think DX12 fixes VSync's input lag dilemma.

[SQZY98]

G-Sync is exclusive to Nvidia GPUs

FreeSync requires AMD GPUs

With those technologies you can often archieve smoother gameplay in certain fps ranges - depends on the monitor.

 

V-Sync is usable on both sites but locks the FPS to 60.

[VZX]

40 minutes ago, SQZY98 said:

With those technologies you can often archieve smoother gameplay in certain fps ranges - depends on the monitor.

 

V-Sync is usable on both sites but locks the FPS to 60.

Variable refresh rate doesn't make your game smoother. 50 FPS will still be 50 fps with GSync/FreeSync display. It's less smoother than 60 fps in non-FreeSync/Gsync monitor.

 

What FreeSync/G-Sync does is tackling both screen tearing and stuttering problem at the same time

VSync ON will remove screen tearing completely, however stuttering problem will occur if the frame rate dips below the monitor refresh rate.

VSync OFF will ensure there will be no screen stuttering, but screen tearing will be apparent once the frame rate goes under or beyond the monitor refresh rate.

 

V-sync doesn't "lock" the FPS to 60. It caps your FPS to be as high as your monitor refresh rate.

 

[Scionyde]

I'm a tad out of the loop, so if there's been developments since this article I'm unaware of them. Basically, it seems that the handling outside the VRR window is different between G-sync and Freesync.

 

(Source)

 

Quote

First, we need to look inside the VRR window, the zone in which the monitor and AMD claims that variable refresh should be working without tears and without stutter. On the LG 34UM67 for example, that range is 48-75 Hz, so frame rates between 48 FPS and 75 FPS should be smooth. Next we want to look above the window, or at frame rates above the 75 Hz maximum refresh rate of the window. Finally, and maybe most importantly, we need to lookbelow the window, at frame rates under the minimum rated variable refresh target, in this example it would be 48 FPS.

AMD FreeSync offers more flexibility for the gamer than G-Sync around this VRR window. For both above and below the variable refresh area, AMD allows gamers to continue to select a VSync enabled or disabled setting. That setting will be handled as you are used to it today when your game frame rate extends outside the VRR window. So, for our 34UM67 monitor example, if your game is capable of rendering at a frame rate of 85 FPS then you will either see tearing on your screen (if you have VSync disabled) or you will get a static frame rate of 75 FPS, matching the top refresh rate of the panel itself. If your game is rendering at 40 FPS, lower than the minimum VRR window, then you will again see the result of tearing (with VSync off) or the potential for stutter and hitching (with VSync on).

But what happens with this FreeSync monitor and theoretical G-Sync monitor below the window? AMD’s implementation means that you get the option of disabling or enabling VSync.  For the 34UM67 as soon as your game frame rate drops under 48 FPS you will either see tearing on your screen or you will begin to see hints of stutter and judder as the typical (and previously mentioned) VSync concerns again crop their head up. At lower frame rates (below the window) these artifacts will actually impact your gaming experience much more dramatically than at higher frame rates (above the window).

G-Sync treats this “below the window” scenario very differently. Rather than reverting to VSync on or off, the module in the G-Sync display is responsible for auto-refreshing the screen if the frame rate dips below the minimum refresh of the panel that would otherwise be affected by flicker. So, in a 30-144 Hz G-Sync monitor, we have measured that when the frame rate actually gets to 29 FPS, the display is actually refreshing at 58 Hz, each frame being “drawn” one extra instance to avoid flicker of the pixels but still maintains a tear free and stutter free animation. If the frame rate dips to 25 FPS, then the screen draws at 50 Hz. If the frame rate drops to something more extreme like 14 FPS, we actually see the module quadruple drawing the frame, taking the refresh rate back to 56 Hz. It’s a clever trick that keeps the VRR goals and prevents a degradation of the gaming experience. But, this method requires a local frame buffer and requires logic on the display controller to work. Hence, the current implementation in a G-Sync module.

 

[Glenwing]

1 hour ago, Scionyde said:

I'm a tad out of the loop, so if there's been developments since this article I'm unaware of them. Basically, it seems that the handling outside the VRR window is different between G-sync and Freesync.

 

(Source)

 

 

This is outdated, with more recent AMD drivers FreeSync monitors follow the same behavior as G-Sync, and double the refresh rate while maintaining FreeSync when passing below the minimum FreeSync level. This effectively eliminates minimum FreeSync ranges.

[Scionyde]

41 minutes ago, Glenwing said:

This is outdated, with more recent AMD drivers FreeSync monitors follow the same behavior as G-Sync, and double the refresh rate while maintaining FreeSync when passing below the minimum FreeSync level. This effectively eliminates minimum FreeSync ranges.

Ahh, good to know.

[Glenwing]

3 hours ago, VZX said:

Variable refresh rate doesn't make your game smoother. 50 FPS will still be 50 fps with GSync/FreeSync display. It's less smoother than 60 fps in non-FreeSync/Gsync monitor.

 

What FreeSync/G-Sync does is tackling both screen tearing and stuttering problem at the same time

VSync ON will remove screen tearing completely, however stuttering problem will occur if the frame rate dips below the monitor refresh rate.

VSync OFF will ensure there will be no screen stuttering, but screen tearing will be apparent once the frame rate goes under or beyond the monitor refresh rate.

 

V-sync doesn't "lock" the FPS to 60. It caps your FPS to be as high as your monitor refresh rate.

 

V-Sync does lock your framerate to a multiple if the monitor refresh rate. If your framerate falls below 60fps, it will drop to 30fps, and stay locked there until you're getting 60fps+ again. It's not simply a framerate cap.

 

And yes, variable refresh rate does actually make your gameplay somewhat smoother. 50fps is not the same at any 50+ refresh rate. 50fps at 50Hz is smoother than 50fps on 60Hz. If the monitor refreshes 60 times per second but is only fed 50 frames, then 10 of those frames will be repeated twice, resulting in a bit of unsmoothness which is eliminated with variable refresh rate. Of course it is not magic, 10fps will be unplayable no matter which way you slice it, but variable refresh does help make things smoother. As has been said, 40-45fps feels like 60fps with G-Sync active.

[Nena Trinity]

Freesync is cheaper!