Any drive that is UATA/UDMA should work fine on any 80-wire cable, round or flat. Riddle me this... If you have to plug a hole to make it work, that would have to assume that there is no pin on the drive that uses that hole, else you couldn't plug it in with the hole plugged. If there is no pin, then why do you have to plug the hole? So that story can be dismissed as BS!
. I've used only 80-wire flat cables for a long time - even with non-UDMA drives with no problemo, since I read somewhere that some mobo IDE adapters were more stable with matched cables (80 and 80). So just set all your drives to CS (Cable Select) and fly (middle connector will be Slave on channel, end connector will be Master on channel, blue connector goes to mobo). My new MSI X48 Combo drive has a UDMA-2 (33MHz) interface and it works fine on the round cable I get from SVC.
.bh.