It now appears that one culprit might have been a slow, progressive failure of one of the 8800 GTX cards coupled together in a SLI configuration. The one card always ran a bit hotter than the other, which I put down to less air-flow in the secondary PCI-e slot lower in the case and near a sound card. However, when the crash problems became especially severe, it was observed to be running 30+ degrees hotter than its peer.
After much testing, I discovered that I could get the game stable by turning off SLI and running with the primary card only. I tried moving the secondary card to the primary slot and running the game off of that one card — and it would lock right away. Running solo on the other card was stable for an hour or more last night.
What is interesting is that the card that failed would do so even if the temperature was normal. It would run very hot in SLI, but not as the solo card.
The eVGA card that appears to have failed was out of warranty, but eVGA is indicating they might let me RMA it anyway. If so, they get high praise for customer service.
So, if you are getting crash problems with SLI, try the game with just one card at a time. Also, look for one card running notably hotter than the other as a sign of potential trouble.
What is nice is that the solo 8800 GTX will still run the game with everything maxed out at playable frame rates on an AMD 6000 rig. Those are still very nice cards and used ones can be found for less than $100. The 8800 GTX card I have left will go to my daughter’s rig, with another joining it if eVGA does the RMA.
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