Just started using this with my 5x7950 rig.  It seems whenever the pool is set to X13, one of my GPU goes sick.  X11 seemed stable for a while.
I've been running this rig in scrypt mode for months.  I have a GPU go sick about once every 2 weeks. I simply reboot.

However, mining X13 it's going dead in a couple minutes.

Any suggestions?    I've tried lowering the GPU clock for it, but that didn't make any difference.