Ubuntu 13.10 doesn't recognize third GPU

[SheepOnDrugs]

'Sup,

I just got my new GPU today and built it into my rig.
So far I've got 2x R9 280X Battlefield 4 Edition and my new one is a R9 280X XFX which Ubuntu doesn't recognize.
I already reinstalled all my drivers and did all things like:
export DISPLAY=:0
export GPU_MAX_ALLOC_PERCENT=100
export GPU_USE_SYNC_OBJECTS=1

aticonfig --lsa
sudo aticonfig --adapter=all --initial
sudo aticonfig --adapter=all --odgt

But nothings helps, even after several reboots.

lspci | grep VGA doesn't recognize my third GPU either although it's working (fans are blowing). You got any ideas?