oclHashcat incompatible with new AMD beta drivers
When running the new AMD beta drivers designed for RAGE and Battlefield 3, oclHashcat makes the screen black out for a few seconds before the screen comes back. oclHashcat hangs, does no processing and is unresponsive.

I know I shouldn't expect anything else from beta drivers, but since my own GPU software works on the same drivers, it might be worth looking into.

Link to the drivers: http://support.amd.com/us/kbarticles/Pag...verV3.aspx
use catalyst 11.4: http://hashcat.net/wiki/oclhashcat_catalyst_forceware

i also tried catalyst 11.10 beta 3 - no difference at all (also no black screens).