Just built a WHS box with the following -
ASRock A780FullHD motherboard, AMD 5050e, 2GB RAM. The only hard disk connected is a 500GB SATA Maxtor from my pc, which I've been using without problems, and is fine under chkdsk and SMART.
I'm using the WHS X:\Files build, enabled AHCI, and the install detected the drive (and old partitions). It takes a long time to 'clean physical disk 0' and then gets stuck on the 'formatting the system volume' stage, for >3hrs. The progress bar doesn't move. I tried this twice.