I've written about how adaptive refresh synchronization on displays works in the past, but the long and short of it is this: GPUs and displays presently exist independently of one another, with the display expecting a frame delivery every 16ms to 8ms (60Hz vs. 120Hz). If a frame is not delivered in that time and v-sync is enabled, the display produces a stuttering effect that causes "lost information" to the user -- meaning that the previous frame is repeated. Repeating a frame looks like visual lag or choppiness (hence "stuttering"), so most gamers disable v-sync in favor of the much more predictable "screen tearing." It's generally a choice between tearing and stuttering. Tearing means that the display will draw frames immediately upon reception from the GPU, even if the previous frame is still being drawn on part of the monitor. Ultimately, we end up with game elements that look "disjointed"—torn—but the benefit is that we don't lose information (no stuttering). It looks like this:
This was all resolved with G-Sync. See the below video to learn about how G-Sync and adaptive synchronization work:
But within months of nVidia developing this technology, AMD announced "FreeSync," which is the company's no-hardware counter to G-Sync. At Computex 2014, AMD notified the press that their Adaptive Sync technology is being added as an extension to the DisplayPort 1.2a standard in a firmware update; the extension means that monitors which already host the required hardware and VBLANK VESA control will be able to run project FreeSync with patching. It is worth noting that AMD's "FreeSync" codename means free as in free speech, not free as in free beer -- it's probable that the tech will still cost something to implement for consumers.
AMD showcased its adaptive synchronization on a shipping standalone display at Computex 2014. The significance of the "shipping" item is that no hardware updates were involved, only firmware updates and a DisplayPort 1.2a interface. AMD tells us that their display at Computex was operating at only 60Hz, but notes that this is sufficient for demonstration purposes.
The slow speed to market tells us that AMD is potentially facing more difficulty than they let on. NVidia uses an FPGA board and RAM to handle a lot of the of the display to the GPU communications, with the RAM aiding in frame smoothing without producing awkward input or other latencies.
We have been told to expect FreeSync's release date as September, 2014.
- Steve "Lelldorianx" Burke.