Just not yours!
From the specs at
One of the following Macintosh computers: http://www.apple.com/aperture/specs.html
* Power Mac G5 with a 1.8 gigahertz (GHz) or faster PowerPC G5 processor
* 15- or 17-inch PowerBook G4 with a 1.25 GHz or faster PowerPC G4 processor
* 17- or 20-inch iMac G5 with a 1.8 GHz or faster PowerPC G5 processor
This includes my PowerBook that is over 2 years old.