your mac should be able to use a 120 GB harddrive with no problem without a PCI card. its the ATA/6 capability that you wouldnt have in the 450 - and that is only needed to support drives above 136 GB. sandor On Jan 4, 2004, at 9:49 PM, S Austen wrote: > Hi, > > I'm running G4, 450 MHz, AGP with original 20 GB hard. I just > purchased a Western Digital ATA 120 GB drive. I know that to take > full advantage of my new drive, I need to install a PCI card. > However, until I buy the new card, can I install the new drive, format > it, and use it, then install the card later without losing data? > > thanks, > > Steve >