I'm running 280gtx sli (Asus) since 2 or 3 days without any freezes, locks etc @0801
using vista64 on a raid0 with velociraptors, 177.41 forceware and 15.17 nforce but well I had no probs with my 2 9800gx2, too.
gonna give 0804 a try.
I will check if it remains stable and test it with a 3rd asus