Xfwm has had compositing since 4.12 you absolute fucking retard. It has fuck all to do with compositing. If you're running Intel graphics, it's pretty common to get tearing with compositing if you don't enable TearFree in xorg. If you're having tearing problems, just do the following:
sudo nano /etc/X11/xorg.conf.d/20-intel.conf
Identifier "Intel Graphics"
Option "TearFree" "true"
There, that was fucking tough.