The same problem here. I've got 4 gb of ram, so far 8 (64bit) has been working flawlessly (much faster than XP). Drivers updated. I would like to single out the problem. Is it:
a) bios/chipset ( I've got nvidia 780i sli chipset)
b) ssd drive I've installed OS on
c) sb audigy card ( old known problem of not having drivers for the midi port)
d) other :)
I don't have time to pull everything out one by one and check, trying to install 8.1. Not saying that pulling out the motherboard could present a little of hassle :)
Thanks in advance
P.S. as almost everyone else I don't any ramdisk software, weird partitioning, second OS, no encryption etc. etc.
edit: maybe its the q6600 processor? (64bit) :)
For what it's worth, I also run a Q6600, 4GB RAM, 64-bit OS, and an nVidia video card, although mine's much older than yours (GTX 280 running v. 327.23)