A fast processor (G4), now obsolete because of the GeeFive (G5).

Has been used in the GeeFourCube, GeeFourPowerBook (Titanium and Aluminum incarnations), GeeFourPowerMac, GeeFourXserve, GeeFouriMac, GeeFoureMac, and now, the GeeFouriBook.

http://a1600.g.akamai.net/7/1600/51/634ec07d933a12/www.apple.com/hardware/powermacg4/images/indextop02022003.jpg

One might note that in the technical parlance, what Apple refers to as the G4 is actually the PPC74xx. The first was the 7400, and I think they’ve made it up to 7455, and possibly beyond. One should note that it’s neither that fast, nor obsolete, though.