Hello Chris M,
Have you found a way (preferably automated) to trigger the crash on demand? Based on the suspicion that PowerMizer is involved, we tried running the following on our M6500 overnight to see if it would crash, but it didn't:
while true; do nvidia-settings -a [gpu:0]/GPUPowerMizerMode=$[$RANDOM%2]; sleep 2; done
This basically randomly changes the PowerMizer mode between "Adaptive" and "Prefer Maximum Performance" every two seconds. If the system is otherwise idle while this runs, then it ought to switch between the fastest and slowest clocks. Does your system crash when running this for extended periods of time? If not, can you identify something that will so that we can try to get ours to crash?