I've compared Firefox performance during 4k Youtube video playback on 20.2.2 against 20.4.1 and on newer driver the performance became significantly worse.
An example, this video (change quality to 4k)
Start/stop the video and scroll-up/scroll-down the page. At least on my system Firefox stutters.
Anyone encountered the same?
tested - no lagging here
ps Matsimus is a good proud mong