If you make your own g5 system - make sure you get the 7800 graphics card.

The same problems that Aperture users have noticed also affect Catalyst.
The 6600 isnt do great.

http://www.macfixit.com/article.php?...60523083425255

Like many others when Aperture was released I ordered a new PowerMac to be able to run Aperture. At the time the nVIDIA GeForce 6600 was a recommended system. Sometime after the release of Aperture 1.1 it was moved over the minimum system requirements. While I do not expect Apple to maintain full backwards system compatibility I think this is certainly excessive. As it currently stands Aperture is painfully slow and all indications are the only fix is upgrading my graphics card to the GeForce 7800 GT.