You're in luck. The Quicksilver 2002 revision, although it only has an ATA/66 controller onboard, was the first PowerMac line to support 48-bit addressing for hard drives. Therefore it'll support any size hard drive that is compatible with the ATA bus. Anything before the Quicksilver 2002 is limited to using only 128 GB of any drive you install, regardless of the partitioning scheme.