Go to AppleCare Knowledge Base Article ID: 58418, Power Mac G4: How to Differentiate Between Models." URL is http://docs.info.apple.com./article.html?artnum=58418 . The Yikes (Model M7631) is a modified G3, has PCI graphics, and needs a PCI card to decode DVD movies and kind of an orphan child. The Sawtooth (Model M66921) has AGP graphics and will software decode DVD movie with DVD Player. I have the next in the series, the Sawtooth with AGP graphics and Gigabit Ethernet, modified with and additional hard drive, PowerLogix PMG4-1000 MHz processor upgrade and a Radeo 8500. The is probably the most flexible of the early G4s and preferred because of its ease of upgrade... and you don't have to mess with digital audio and all the USB related problems. Mike >So how does one determine whether a G4 is a Yikes or a Sawtooth? I >bought a G4 >400 from a pawn shop, and I can't tell. Is there a definitive way to tell? > >Thanks in advance, >-Lavode -- Almost never pointless.