I have a Sil 3512A Raid controller on the motherboard, and had two 500GB harddrives installed and operating with no issues. Motherboard is a GA-7n400 Pro 2 Rev 2 (Gigabyte). I removed the old harddrives and installed two 750GB harddrives, but now the computer will not boot if they are connected. The BIOS will detect the first drive, and then lock up. If I disconnect or swap cables, it detects the other drive and locks up. I have disconnected both drives, and reconnected after booting, and they are detectable, formattable, etc., as separate drives. I have tried the manager program from Silicon Image, and it sees both drives when I connect them, but cannot raid them. It runs the Create RAID set wizard, but nothing happens when it says it is done. It gives me different options for transfer mode, but not sure if I should change those settings (PIO, MDMA, UDMA), but they are currently set to UDMA6. I was thinking of putting a SATA RAID PCI card in and see if that would solve the problem, but will take time to receive on from the online store (local stores don't carry them). Any ideas why the drives lock up the BIOS? I am trying to set up the Home Server, and want as much storage space as possible. Thanks for any inputs. If more info required, please let me know..will be glad to provide.