I have two 160GB Seagate SATA drives in a RAID 0 configuration. When this problem first started, they would beep every one in a while, causing about a 2 second hang. It's now to the point where they are only intermitently seen by the system (even the RAID controller).
Are both the drives bad? Or is this a problem with the motherboard? I've also seen some people who had this problem said it was their power supply voltages, but mine aren't that bad (12V+ is 12.16V, 5V+ is 4.35V).