If it's crashing, it sounds like the overclock it too high or the temperature is too high. Lower the overclock until the system stops crashing. If it was nix you could setup a script in the case of a failed gpu.
I'm running 4x 5830 @ 950/300 but having a small problem with occasional crashes on the main GPU. Basically the graphics card driver crashes and reloads itself (it does this fine) but mining on that particular GPU will stop and not resume correctly.
Why does it crash? Is it because idle clock for memory is too low and windows does require the main GPU's memory to be "un-idle" sometimes?
Is there anyway to automatically recover from the crashed driver?
Thank you!