DisplayPort Only, For Now
The arrival of Adaptive Sync displays suffered the same marketing problems as HDR, with some manufacturers not adhering to the standards set by AMD and NVIDIA. The solution has historically been to go to VESA to have proper certification drafted, along with penalties for products that fall short of the claims they make about refresh rates, response times and judder. To try to resolve this issue VESA have introduced two standards, Adaptive Sync and Media Sync.
In order to be a VESA Certified Adaptive Sync or Media Sync display the monitor cannot have over 1ms of judder on 10 different refresh rate standards, from the Hollywood film standard of 23.976 Hz through to US Sports broadcasts at 59.94 Hz. In part this is to end frame-doubling or tripling the Hollywood rate to try to avoid the huge judder that can introduce. In addition they test the monitor at random refresh rates to ensure there are none that hurt the hertz, after all the point of having variable refresh rates is to smooth your viewing experience when refresh rates vary.
For monitors with overdrive, VESA tests to ensure that feature does not introduce more than 20% overshoot and 15% undershoot in VESA’s Gray to Gray tests. Those GtG tests are also run 20 times in different combinations, including with black, dark gray, mid-gray, light gray, and white; the test are temperature controlled as a warmer room can temporarily increase GtG results.
The difference between the two VESA Standards is the maximum refresh rate. Media Sync is applied to variable refresh rate displays which have a maximum of 60Hz and are for watching movies and other media. Adaptive Sync displays are the ones with top high refresh rates, at least 60 to 144 Hz if not higher, which gamers use to great effect.