I have the following system:

Powermac G4 Quicksilver (733MHz G4, 256MB RAM)
Upgraded to G4 1.2GHz (OWC) and 1.25GB RAM
I recently installed a 6800GT 256MB flashed for Mac
Running Mac OS X 10.3.9

2D Performance is ok, I'm running a 20" widescreen LCD at 1680x1050 using the DVI port

But when benchmarking 3D performance or running games my ATI 8500 64MB performs better.

My hunch is that its a driver issue or firmware issue. Has anybody ran into a similar problem?

I'm thinking of upgrading to Tiger to see if that makes a difference, otherwise I think I may have to reflash the card or something.

Just looking for some advice and direction.

Thanks.

To be honest, I've noticed the same type of occurence. I have a flashed 9800 Pro and a regular 9000, and for most things the 9000 outperforms the 9800. Same thing with Nvidia cards, A flashed nvidia fx5200 256mb was outperformed by a standard fx5200 64mb. All of them were tested in the same G5.

It's the firmware. Sometimes you have to edit the ROM to the right specs of the card. For a example a mac nVidia FX 5200 128MB backup ROM was used on a PC nVidia FX 5200 256MB. It would only use 128MB of the memory even if system profile states it's 256MB. It's weird but thats how it works.

I agree that it must be firmware.  thats the only way an 8500 could outperform a 5200.

upgrading to tiger is a good idea no matter but it still won't solve your firmware issue..