Well, this problem recently started to happen to me. I have Windows 8 Drivers for my razer naga, when I put it to sleep mode it does not wake from it, lights are still off, I have to put it into sleep mode again and then it might work. It usually turns on after the second sleep awaking. Its quite annyoing.
Both my computers would not wake after sleep once windows 8 was installed.
I updated both chipset drivers from the amd site. NOT from the motherboard page but from the general "amd chipsets" for windows 8 page. Both computers seem to be working now. (note: neither of my motherboards have windows 8 drivers listed on the motherboard pages yet)
I think its the AHCI drivers specificaly, but not sure.