52 is fine for a GPU, mins hits 66 occasionslly, GPUs can withstand a much higher temp.
to me it sounds like CPU thing, if it errored in P95.
back me up on this people, but you may want to try upping to core voltage to stabalise it. find out what it is set to at the moment, by looking in the bios, under advaced chipset features. have you overclocked it?