For months I've been hearing how OS-X is so demanding and that you really need a G4 to run it properly. I owned a G4 tower, so I assumed the talk was correct. Then my dad sent me an old Beige G3 233 for Christmas. I put in 512 MB of RAM, a SCSI card and an 18 gig Seagate drive and an ATI Radeon card ... then installed OS X. You know what? It flies. It beats the crap out of my Pentium III 600 on Windows XP. I've ordered a G4-500 Sonnet upgrade, but I'm not in a hurry to receive it, this system does everything I need to do (including running MS Office v.X.) My point: OS-X demands one thing, RAM. Feed it memory and it's happy. It doesn't hurt to have a fast HD and a top-notch video card, but that's true for any computer in any OS.