Apple PowerMac G5 Memory Upgrade Configurator - choose your Model:

1.6GHz
1.8GHz (Late 2004)
1.8GHz / Dual 1.8GHz/2GHz
Dual 1.8GHz (June 2004)
Dual 2.3GHz (Early 2005)
Dual 2.5GHz (June 2004)
Dual 2.7GHz (Early 2005)
Dual 2GHz (Early 2005)
Dual 2GHz (June 2004)
Dual Core 2.3GHz (Late 2005)
Dual Core 2GHz (Late 2005)
Quad 2.5GHz (Late 2005)