I’ve found that if I’m listening to youtube (music) on another monitor I get the choppyness. If I pause the video, the issue disappears entirely. If I minimize it, or go to another tab I get significantly less but it’s still there.
Disabling hardware acceleration in Firefox fixes it.
I’m guessing that Blizzard’s having issues with DX12 and contention/prioritization. In the meantime, making WoW the only thing using the graphics card, or removing hardware acceleration, seems to be a highly effective fix - for me at least.
i9 7980 XE @ 4.2GHZ, 64GB DDR4, Optane 905 primary disk (wow installed there), Win10 20H2, 1080TI x2 in SLI. Latest GeForce drivers.