Apple Mac Pro Memory Upgrade Configurator - choose your Model:

2006 Model 2.0/2.66/3.0GHz
2007 Model 3.0GHz
2008 Model 2.8/3.0/3.2GHz
2009 Model 2.26/2.66/2.93GHz 8-Core
2009 Model 2.66/2.93/3.33GHz Quad-Core
2010 Model 2.4GHz 8-Core
2010 Model 2.66GHz 12-Core
2010 Model 2.8GHz Quad-Core
2010 Model 2.93GHz 12-Core
2010 Model 3.2GHz Quad-Core
2010 Model 3.33GHz 6-Core