I remember reading a lot of Mac user complaints about the G5 PowerMac models when they first came out, and how the last models of the G4 PowerMac were out performing the early G5 PowerMac's, until more optimization of perhaps MacOSX and certain software titles was completed, to better utilize the G5 architecture. That, plus the poor performance of some of the 9600 video card models, which Bigfoot has confirmed, that some models were slower than the top of the line earlier 9000 series cards.

It does not surprise me that some software runs slower on the G5, when combined with specific models of the 9600 video cards.

The TV & Movie production special effects company I purchased seven G4 PowerMac computers from on eBay, had continued using many dual 1.25GHz G4 PowerMacs to run MacOS9.2.2 & AVID software until just a few years ago, when they switched to using Intel powered systems and some other software solution. IIRC, the last show that the old G4 PowerMacs were used to produce graphics & effects for was the Grammy Awards show aired in 2010. I was surprised that such old systems had continued to be used that long, when newer faster systems were available, long before that date.