Comment # 7 on bug 79551 from Michel Dänzer

(In reply to comment #6)
> if in /etc/environment set DRI_PRIME=1 and in /etc/xprofile set xcompmgr -c &
> some apps will display with artifacts (part of window freezes when scrolling)

Apps using PRIME, or others?

BTW, just xcompmgr -a should be enough, no need for -c.