Ok, so, I tried another thing.
On the/etc/X11/xorg.conf.d/20-intel.conf
file, I deleted Tearfree,
I replaced it by AccelMethod uxa
AND… The tearing at scrolling on Telegram and Firefox just disappeared BUT… The problem is not solved because the tearing on my multimedia content (Vivaldi, Firefox, VLC, Gnome MPV)… Just reappeared.
As everyone knows, I just cannot put on the file Tearfree
and Accelmethod uxa
together, because these two options are not compatibles.
Justin So, are you sure the Intel builds configuration for Solus is right on my CPU ?
I mean : maybe a bad configuration for the Intel builds in Solus kernel is… What it causes my bug.
When I was a Linux Mint Cinnamon user, I never had this problem.
I suppose this is a very specific Solus problem with my very specific SandyBridge CPU…
Otherwise, thank you so much for trying to help me. If someone knows something, I will be eternally grateful.