Fglrx is a pretty broken and crappy driver for AMD (formerly ATI) graphics cards.
 Working combination for Radeon 7850
Radeon 7850 cards are basically stable with a combination of:
- Kernel 3.12.X
- xorg-server 1.14.X
- ati-drivers/fglrx 13.11_beta6
^^ this works and you can use cgminer at -I12 or -I13 without it interfering with normal desktop usage.
- ati-drivers version 13.4 is a completely broken pile of donkey dong with this card.
- ati-drivers version 13.10_beta is the first version not to suck completely with R7850.