Awesome. Thanks for your help! Changing from 8 USB Ports to 6 USB Ports in BIOS finally fixed my sleep/hibernate/fast startup problems too. Of course now the two USB ports on the front of my case don't work, but I wasn't using them anymore anyway (I have a USB hub on my desk) so it's no great...
I've put together some additional information on this issue, though I am not really any closer to solving it.
If I try to put the computer to sleep, after it immediately wakes itself back up, the process "System interrupts" starts perpetually chewing 10-20% of CPU cycles. This suggests a...
Win8 RTM: Can't sleep, hibernate or hybrid-shutdown
I just upgraded to Windows 8 Enterprise x64 RTM yesterday, and have noticed an annoying problem that wasn't present under Windows 7 Enterprise x64 (which I was running previously). Specifically, the machine will not sleep, will not hibernate...