Looking at the previous dumps.. We see a lot of memory related error.. Now.. These could very well be RAM or the processor L1 cache or Video RAM.. Now as far as we have seen in this post ... You have done the memtest on the RAM which passed... you dont have any Bugcheck 0x124 errors so no problem with the processor cache....
So that leaves us only With Video RAM...Use this
Video Memory Stress tool to test.. If you see any errors ... that could very well mean your Graphics card is at fault.