After too many false starts and red herrings, I'm sending my video card in for RMA replacement. I currently think my problem is caused by a failing video card. I've tried to document what I could with regard to troubleshooting here: http://one-miguel.blogspot.de/search/label/Skyrim Everything from turning off speedstep, core parking, Bethesda support, etc, etc. I've put in an older video card since I've packed my GTX 570 for RMA and haven't seen the crash yet. Note that any and all stress tests, diagnostics, etc, don't show any issues with the video card. But the logic can't be denied: change video card, problem goes away. Must be the video card.