What is V-Sync, G-Sync, and FreeSync?

[Thunder Squirrel]

So I'm looking to buy a new gpu  and I am considering amd as an option, but I don't fully understand what FreeSync is. Currently with my NVidia gpu, I enable V-Sync and to my understanding, all that does is just limit the frame rate according to the hrz of your monitor. But what about tearing? Does V-Sync help with that? Is G-Sync the same as V-Sync? And on amd's side, what is FreeSync? I'm just confused about what these technologies are and how I can utilize them. (Compatibility wise that is.) Any help is appreciated. Thanks!

[Alex Carr]

Short for Vertical Sync, Vsync is a display option found in some 3-D computer games that allow the gamer to synchronize the frame rate of the game with the monitor refresh rate for better stability. If the Vsync is turned off, gamers might obtain a higher frame rate but this action may introduce artifacts in the game.

 

NVIDIA G-SYNC is groundbreaking new display technology that delivers the smoothest and fastest gaming experience ever. G-SYNC's revolutionary performance is achieved by synchronizing display refresh rates to the GPU in your GeForce GTX-powered PC, eliminating screen tearing and minimizing display stutter and input lag.

 

FreeSync is the brand name for an adaptive synchronization technology for LCD displays that support a dynamic refresh rate aimed at reducing screen tearing.FreeSync was initially developed by AMD in response to Nvidia's G-Sync.

[Shreyas1]

if you are getting amd, get freesync. g-sync wont work on amd graphics cards. I think they limit screen tearing

[Thunder Squirrel]

Well now that I understand what they do, will all of these technologies work with all monitors?

[minibois]

V-Sync is in the game and is supported by all monitors and both AMD and Nvidia GPU's. G-sync is only for Nvidia GPU's, Freesync only for AMD. G-sync and Freesync both have to specifically supported by the monitor.

 

With that out of the way.. the differences.

V-Sync makes it so your fps doesn't go above your monitor refresh rate (it's Hz or 'fps'), but does this by delaying frames , increasing the lag every so slightly.

Freesync and G-Sync both make it so the monitor refreshes whenever a new frame is shown (within a window of course, which is between  30 and 144Hz for Freesync I thought.)

 

All these technologies are supposed to eliminate screen tearing, as  that is something that occurs when a monitor's top and bottom half show a different frame. When a screen updates itself, it grabs the latest frame of your game, but when halfway through making the image on screen a new frame of your game shows up, it will show that. Freesync and G-Sync synchronize a new monitor refresh with a new fps, V-Sync delays frames so they show up when your monitor needs a new frame.

[Alex Carr]

1 minute ago, Thunder Squirrel said:

Well now that I understand what they do, will all of these technologies work with all monitors?

the actual monitor shouldn't be a problem, if there is any problem at all it would probably be refresh rate.

[cj09beira]

2 minutes ago, Alex Carr said:

the actual monitor shouldn't be a problem, if there is any problem at all it would probably be refresh rate.

freesync and g-sync need the monitor to have a specific hardware to work, amd's implementation is basically free, nvidea's implementation costs a lot (about 100 bucks more than a similar freesync monitor)

[Thunder Squirrel]

Sounds good, but my last question is does V-sync prevent tearing or is it only for an fps cap?

[Guest]

7 minutes ago, Thunder Squirrel said:

Well now that I understand what they do, will all of these technologies work with all monitors?

Only if monitor supports it

[Enderman]

 

[minibois]

3 minutes ago, Thunder Squirrel said:

Sounds good, but my last question is does V-sync prevent tearing or is it only for an fps cap?

It mostly does, it's not perfect so some tearing may still occur.. But it will mostly be gone.

[Thunder Squirrel]

Alright than I think I get it. Thanks everyone!

[aithos]

V-Sync is vertical sync, it forces the frame-rate to cap and match the refresh rate of the monitor.  It works with any monitor, but also causes substantial input lag.  Generally it's fine for single player games, but you want to have it turned off for any online or multiplayer game because the visual improvement doesn't offset the negative of input lag.

 

GSync is nVidia's adaptive sync, it is similar to V-Sync except that it forces the refresh rate of the monitor (within the range) to match the FPS the graphics card is outputting.  It resolves screen tearing and makes for smoother motion when your graphics card is incapable of maintaining the native refresh rate of the monitor.  It also adds input lag but supposedly less than V-Sync.

 

FreeSync is the not quite as good version of GSync that also works with AMD graphics cards.  I'm not 100% sure whether it works with nVidia GPU's or not, but TBH if you've got a green GPU and intend to get a "sync" monitor you should go for GSync regardless.

 

The thing you're also missing is ULMB, which is the technology originally called Lightboost that was developed for 3D movies/games and adapted by clever programmers to eliminate frame persistence and virtually eliminate motion blur.  It doesn't work with GSync or FreeSync but when you can maintain good frame-rates makes a substantially bigger impact on visual quality than removing screen tearing.

[Mira Yurizaki]

To take this in general, these are ways to address screen tearing, where the frame rate does not line up with the refresh rate.

 

I'm taking this from something I'm working on, but it describes the methods:

VSync

The first method is known as V-Sync, named after the vertical sync (VSYNC) signal. What this does is the GPU will wait until the vertical blanking interval (which in a CRT is the time when it positions the electron beam to the top of the screen) before sending the next frame. If the frame finished early, there's no problem. But if the frame finished late, then it will be displayed at the next blanking interval, which means a delay of one refresh cycle has been introduced. With a faster refresh rate, this lag is lessened, but it can still be bothersome to people.

 

Variable Syncing (GSYNC and FreeSync)

Both of these adjust the effective refresh rate to the current frame rate so that no tearing can occur. This works by instead of the GPU waiting on the monitor to be in a vertical blanking interval to send a frame, the monitor waits until the GPU is done rendering the frame before the GPU sends it over. However, this only works if the frame rate is lower than the refresh rate. It's possible that the monitor remains in the vertical blanking interval until the GPU sends it a signal its ready, and since you can only shrink this interval so much due to timing, this effect only works until the frame rate hits the refresh rate where the minimum blanking interval time is.

 

There's some question of whether FreeSync or GSYNC introduces latency. The only latency either of these can introduce is due to the frame rate of the application changing. While GSYNC has a higher effect on frame rates than FreeSync, the difference is too small to be appreciable by most people (if anyone at all).

 

Triple Buffering (and Fast Sync)

In triple buffering, instead of having two buffers to hold the rendered frames, there are three: one front buffer and two back buffers. The GPU renders a frame to a back buffer as usual, but when it's done, it switches to using the other back buffer. When the monitor gets to its vertical blanking interval, the GPU switches the last back buffer it rendered on with the front buffer. Tearing still does not happen since the front buffer is not swapped in the middle of the monitor displaying it and since the GPU is still rendering as fast as it can, the GPU will send the most recent frame, minimizing latency.

 

While triple buffering has been a feature in some games and video cards, they may have not implemented triple buffering in the method described above. For instance, some applications may simply have had a queue and the GPU always wrote to the oldest buffer, introducing pockets of latency.

 

NVIDIA implemented triple buffering on a driver level called Fast Sync. While there was an option in the NVIDIA control panel, this only affected OpenGL games. Fast Sync brings triple buffering to any 3D accelerated application. There may be an option for triple buffering in AMD cards, but like NVIDIA, this may only work in OpenGL games.

 

When should you use one or the other?

• Not enabling any syncing or triple buffering is used if you want to minimize input lag and you don't mind tearing.
• GSync or FreeSync should be enabled if your GPU cannot maintain a frame rate faster than the refresh rate.
• Triple buffering or Fast Sync should be enabled if you can guarantee the GPU can maintain frame rates faster than the refresh rate.
  • VSync is also an option here, but keep in mind the frame will be at least one refresh cycle late.

 

[Sakkura]

3 minutes ago, aithos said:

FreeSync is the not quite as good version of GSync that also works with AMD graphics cards.  I'm not 100% sure whether it works with nVidia GPU's or not, but TBH if you've got a green GPU and intend to get a "sync" monitor you should go for GSync regardless.

It doesn't work with an Nvidia GPU.

 

But it is just as good as G-sync, if it's well implemented. Some monitors (especially some of the first that came out with Freesync support) will only have a limited range of refresh rates that work with Freesync, so that's something to look out for.

 

Basically Nvidia made its own (expensive) module for the monitor so they can deliver the exact same performance on all G-sync monitors. AMD gives the monitor manufacturers freedom to implement it... including the chance that they'll do a poor job of it.

[TheSuspect]

Nvidia - Gsync

Amd - Freesync

Both - Vsync 

 

Vsync puts a limit to the amount of frames your card displays, the limit being the refresh rate of your monitor. The technology with vsync increases input delay, though. By how much depends on the situation. Gsync and freesync eliminate the issue of tearing, while avoiding the issue of input delay.