The game runs fine on the same system with a R9 280x installed.
So, coming to this threads exciting conclusion, probably just a graphics driver issue.

Running linux mint 20.

Just got it to trigger on l4d2 by alt tabbing out of and into the game, so it's not unique to Factorio.
Looks like everything freezes up (including other applications) while it works on mouse movement. Never seen anything like it.

Koub wrote: Sun Jul 19, 2020 7:13 am Just in case it's linked, I'll leave this here : viewtopic.php?f=49&t=86790

Both stardew valley and l4d2 run fine. The problem also occurs in the games main menu.

I currently dualboot windows/linux mint and cannot play Factorio under linux due to mouse lag.
I've noticed that when moving the mouse in a circle, the mouse pointer will move in a triangle with smooth interpolation between the points.
The mouse has no lag when not in game. The game also runs fine ...