You really should eliminate that xorg.conf file, and if the problem continues,
don't assume it's the kernel driver at fault. Just report a bug if so inclined.
Where would depend on behavior after removing xorg.conf. If it fixes the problem,
there is almost assuredly no bug anywhere at all affecting you. If with
modesetting it's gone, but with xserver-xorg-video-nouveau installed and in use it
remains, then it would be good to report a nouveau DDX bug, though the problem
could be DRI or Mesa. Unreported bugs can go a very long time before a fix occurs,
if ever. What you are now experiencing is not acceptable behavior. 13 years of age
is too young to accept FOSS performance degradation or need GPU upgrade.