i had one that was doing this about 2-3 days ago

it went pretty quickly from being stable at 810/150 @ 1.010v to 720/150 @ 0.990v to 600/150 @ 0.95v

then i decided to try to go to 650/150 @ 0.950v, it crashed.  powered computer off & on (is there some way in linux to not have to do that when a card crashes?? wtf), and now it won't even run at 550/150.  it says 0.00mhash/s, but it does get like the whole 'new work' messages and stuff.

that room is too hot, and i've been too lazy to take it out of the computer.  besides, the 1st gpu can run at 850/150 @ 1.050v now, since the 2nd gpu isnt giving off any heat