FYI: I've got a G5 2.5 Dual PPC and some time ago I was having a lot of trouble with graphics-- slow redraws, quilting (screen pixelation), etc.
My tower came with the NVIDIA G-Force 5200, and I had no idea what an albatross it was until I popped in a Radeon X-800 XT about a half hour ago.
Does it make a difference? Hoooo-yeah!!
The first thing I noticed was that my 23" Cinema was a LOT brighter and sharper. The second thing I noticed was that the screen redraws are tons faster. At first I was leary about tossing too much more cash at my G5, but it feels like I've got a whole new computer.
No more dizzy wiper in SE while zoomed in...
No more long waiting for fades to redraw...
No more worries about having too many windows open at once, although some frugality is still necessary for the sake of the CPU.
The X800 itself may not be in everyone's best interest....Still, a better-than-stock graphics card is one of the best upgrades you make to jumpstart your old PPC.
Just to show you the benchmark differences between the GF5200 and the Radeon XT800:
