From benchmarks that were shown on here or Tom's recently, there's very little difference even between a 4 year old 7200RPM hard drive and a Raptor. There's NO difference between identical drives on PATA or SATA, because no drive comes close to saturating a PATA connection. Using an add-in SATA card could make an equivalent drive SLOWER, because it has to go through the PCI bus. A single drive wouldn't saturate it, but if you have other PCI stuff... If you've got a 120GB drive, it's pretty modern and upgrading it (unless you need additional storage) would be a big waste of money IMO.