The general consensus seems to be that Nvidia’s G-Sync technology is really good. It seems to do a fantastic job of eliminating tearing issues and stuttering issues, and keeps things looking smooth even when the frame rate dips below 60 FPS.
The main issue with it is that you are stuck having to buy a G-Sync capable monitor, and paying an extra $200 or so on top of that. This is an issue right now, because G-Sync monitors are few and far between, and most of them use TN panels that sacrifice quite a bit of quality.
AMD has been silent on the issue, perhaps because they wanted to finish up “FreeSync” in time for CES. The truth is, there has been a VESA spec for variable refresh rates for a while now. This original intention of this feature is to support extra low refresh rates on notebooks – updating the panel 60 times a second when it is showing the exact same image is obviously a waste of battery life. More important to us though, is that when a game drops below 60 FPS, vsync falls apart and we end up with a miserable gaming experience.
As long as the panel supports variable VBLANK timings, and the GPU hardware supports it as well, it should be possible to replicate the effects of G-Sync, without requiring extra hardware.
AMD have been demonstrating exactly this at CES, and Anandtech has the first writeup and video. Check out the video below, with Anand’s experience (you may want to mute your volume to prevent horrific nightmares tonight):[youtube=http://www.youtube.com/watch?v=pIp6mbabQeM&rel=0]
AMD’s demo isn’t quite as nice as NVIDIA’s swinging pendulum, and we obviously weren’t able to test anywhere near as many scenarios, but this one is a good starting point. The system on the left is limited to 30 fps given the heavy workload and v-sync being on, while the system on the right is able to vary its frame rate and synchronize presenting each frame to the display’s refresh rate. AMD isn’t ready to productize this nor does it have a public go to market strategy, but my guess is we’ll see more panel vendors encouraged to include support for variable VBLANK and perhaps an eventual AMD driver update that enables control over this function.
So it looks like if enough LCD panels support this feature, a whole lot of Radeon owners are going to be very happy when this becomes reality. Nvidia should be able to offer the same thing, if they are willing to cannibalize G-Sync….
The question is, how many desktop monitors support this feature? Since it’s aimed at the mobile market, it may take some convincing to get them to do so.