I have a DX58SO motherboard, lastest BIOS, latest updates, on everything, running Windows 7 x64.
I have a WD 2 TB external USB Drive that will not go to sleep, and in the POwer Management, HDD's are told to go to sleep after 20 Min.
I have the same configuration as my previous machine, software, etc., and the drive did go to sleep.
The other thing is, sometimes the computer will take a really long time to get to the POST screen, and I have to hit the reset button to get it there..
Retrieving data ...