Nvidia is adding a new SYNC mode. This mode works especially well with high FPS games, the folks that like to play Counter-Strike at 100 FPS. With this feature, Nvidia is basically decoupling the render engine and display by using a third buffer. This method was specifically designed for that high FPS demographic, the new sync mode will eliminate stuttering and screen tearing with high FPS games and thus offers low latency across the board. It can be combined with GSYNC (which works great with the lower spectrum of refresh rates).
Fast Sync is a latency-conscious alternative to traditional Vertical Sync (V-SYNC) that eliminates tearing, while allowing the GPU to render unrestrained by the refresh rate to reduce input latency. If you use V-SYNC ON, the pipeline gets back-pressured all the way to the game engine, and the entire pipeline slows down to the refresh rate of the display. With V-SYNC ON, the display is essentially telling the game engine to slow down, because only one frame can be effectively generated for every display refresh interval. The upside of V-SYNC ON is the elimination of frame tearing, but the downside is high input latency. When using V-SYNC OFF, the pipeline is told to ignore the display refresh rate, and to deliver game frames as fast as possible. The upside of V-SYNC OFF is low input latency (as there is no back-pressure), but the downside is frame tearing. These are the choices that gamers face today, and the vast majority of eSports gamers are playing with V-SYNC OFF to leverage its lower input latencies, lending them a competitive edge. Unfortunately, tearing at high FPS causes a vast amount of jittering, which can hamper their gameplay.
NVIDIA has decoupled the front end of the render pipeline from the backend display hardware. This allows different ways to manipulate the display that can deliver new benefits to gamers. Fast Sync is one of the first applications of this new approach. With Fast Sync, there is no flow control. The game engine works as if V-SYNC is OFF. And because there is no back-pressure, input latency is almost as low as with V-SYNC OFF. Best of all, there is no tearing because FAST SYNC chooses which of the rendered frames to scan to the display. FAST SYNC allows the front of the pipeline to run as fast as it can, and it determines which frames to scan out to the display, while simultaneously preserving entire frames so they are displayed without tearing. The experience that FAST SYNC delivers, depending on frame rate, is roughly equal to the clarity of V-SYNC ON combined with the low latency of V-SYNC OFF.
