Running Ubuntu 18, playing YouTube videos in Chrome and Firefox stutter periodically like there's a frame rate/refresh rate mismatch.
I've tried setting the display refresh rate to 60Hz, 59.98Hz, and 59.97Hz (only options available, other than 30Hz) but this doesn't solve the issue. YouTube debug info says I'm not dropping any frames. I'm running an i7-8550U with UHD 620 integrated graphics driving a 3840x2160 display.
If I play the YouTube video with mpv, it stutters in windowed mode, but I get smooth playback in fullscreen mode.
If I can't solve the issue, I'll just use the play with mpv plugin, but it'd be nice if the native browser player would work. Any help would be appreciated!