Terrible lag and stuttering with Freesync on when anything is fullscreen on 2 monitors at once (one non-Freesync)


Sep 10, 2016
The problem is that when I'm playing a game on my main monitor, the FreeSync one, and I full screen a video on my other screen, the game begins stuttering badly until I exit the full screen video on the other monitor.

I was playing WoW, frame-rate uncapped, V-Sync on (tried it with V-Sync off too, to be sure), border-less full screen (exclusive full screen is unavailable).

On the other monitor, I put a video full screen, I switch back to WoW, and in about 1 second, I get terrible stuttering. If I stay motionless and look against dark objects, I can see their brightness flash from dark to brighter and back, like something is terribly wrong.

Also tested in an exclusive full screen game. Same results. It sometimes is so bad the screen/system completely freezes up.

Useful information:
GPU: Sapphire Pulse RX 580
CPU: Ryzen 5 1600
OS: Windows 10

Settings info regarding Freesync:
All special features disabled on monitor, only FreeSync enabled, also enabled in Crimson settings
No frame limiter, but I never go over or under the FreeSync range (45 to 144fps) anyway
Vsync off in games but tried it with V-Sync on as well.
Tried on both exclusive and border-less fulls creen games, same results.

Monitor 1: MSI Optix MAG241C 144Hz - this is the one I run the game on
Monitor 2: Generic BenQ monitor 60hz - this is the one I run the full screen video on
Both are 1080p 16:9

Figured out that this actually happens when there is ANYTHING full screen on both screens at once. Regardless of what it is.
Also seems to not matter whether it's exclusive or border-less.

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