I didn't use just memtest, used several. Clear on all counts, including the extensive tests that are done. It is very unlikely that it is bad memory as a result. This looks like it could be a XP to DirectX compatability issue. I've activated Dr. Watson, next time it crashes I'll make sure to check that out. After that, I'll try pulling sticks and perhaps adjust my latency levels up. Also might try raising my DRAM voltage.