KB 933578 - UDMA 5 device performing only at the speed of UDMA Mode 2 after you swap bay devices in Vista?

Read about it here, and get the hotfix if you need it. This is the second Thinkpad specific KB article I've seen on Microsoft's site about Vista. The other one related to flashing the BIOS of the T60 with older flash utilities.

Basically, if you boot up with a slower UDMA device in your Ultrabay, for instance, a DVD-ROM (UDMA 2), and swap it out for the bay hard drive (UDMA 5), the bay hard drive will stay at UDMA 2, without this hotfix.