It just may be a limitation of the bios. Look into ez-bios, it will fool your bios into accepting the full size of the drive.I've got an old K6 on the above mentioned mainboard and this 60GB HDD lying around. However, I can only make use of 32GB. I tried the BIOS updates from dfi.com but that didn't change a thing.
Does anybody have the secret link to the BIOS update I need in order to get it to see the full size?
Milage may vary.