SDB:Switch xf86-video-intel to UXA
Situation
You are using the xf86-video-intel driver and your X.org server shows black artifacts while scrolling in firefox or crashes when using Empathy. The xf86-video-intel X.org driver in 13.1 uses the newer SNA acceleration by default. If you experience this problem, you should switch to UXA acceleration.
Procedure
Open the file /etc/X11/xorg.conf.d/50-device.conf and add
Section "Device" Identifier "Intel Graphics" Driver "intel" Option "AccelMethod" "uxa" EndSection