I started getting random crashes to black screen during gaming. It took a long time to isolate the problem, since the machine passed stress tests without issue, but after pulling my system apart, I finally noticed that the VGA light on the motherboard was lit after crashes.

The fix was to update the GPU VBIOS, using an update tool from the manufacturer. It takes about 2 minutes and I haven’t had a problem since.

I don’t know if this is a problem with 6800XTs generally, or just with this specific model, but if you are having crashes and see the VGA tell-tale is lit, then check if an update is available for yours.