I have a new system with an asrock Z68 Professional and i7. I installed with two 500g 2.5" seagates in raid 0 and have a 60g SSD for RST. I have two 160g sata drives for backups. All is well in this configuration. But when I added my 1TB and 320G drives to the mix, one of the 160g disappears and the 1TB doesn't show up. I can connect any two of these four drives and they are seen and work without issue. But when three or more of these four are connected, only two show up. This is all at the bios level, not just in windows. Is there some limitation on where to connect the drives?