i gave your suggestion a shot in lost coast and really pushed it to force a crash. stuck on noclip and went through scenery and that crashed it nicely. i might try increasing the heapsize some more next time i'm home and see if that helps. does your screen enter standby mode when the crash occurs? that's the most annoying thing about it cos you can't see what's causing the crash.

what nvidia/audigy drivers are you using currently and what level of DX sound acceleration are you using? i've read things about changing bios settings to help things out, but i've never had any success with that.