HD on G5 dual 2.5

[Simon Webb]

Check out this page:

https://www.everymac.com/systems/apple/powermac_g5/index-powermac-g5.html

You should find the info about your particular G5 there. If you find that your system is, in fact, a PCI-X version, then avoid the ATI Radeon X1900 and go for the ATI Radeon X800 XT.

Best of luck.