Just in case I failed to think of all alternatives, are there any faster nVidia cards, suitable for this 2x AGP Sawtooth machine, that are comparable in peformance to the Radeon 9800 Pro
The Radeon 9800 Pro is the fastest 2x AGP card available, in any flavor.
If none are as fast, what is the fastest nVidia, and how close does it come to the performance of the Radeon 9800 Pro?
That would be the 6200, which we already discussed.
One note about the 6200, is that there are often problems with use in Leopard. If you were to upgrade the processor and move to Leopard, you would probably need a new graphics card.
Also, do you think a used Radeon 9800 Pro 256Mb version will be OK, in comparison to a brand new Radeon 9800 Pro 128 version?
A used one is 50/50- never know what you're getting. It is also a
very rare bird.
As for performance, in graphics benchmarks (Open GL, XBench) scores only improve by 6-10% with the 256MB version. My experience is that the 256MB version only offers a frame or two per second (in games)
real performance improvement over the 128MB version.
If the 256MB version is a real good deal, OK. Otherwise, the 128MB version will not dissappoint.
Check flashed 9800 Pro cards. The 128MB version (new, but called refurbished) is only around $90 on
eBay (linked seller is very reliable). A good performance buy, with
no difference from the real Mac Edition at over $200.
This concerns any heat output or other issues potentially limiting the service life of the cards.
That would be the 9800's fan. It is notoriously short lived. Replace the fan with a
Zalman VF700-Cu or VF900-Cu and all worries about heat and longevity are gone. (Go ahead and get an LED model, it's FUN!) 😉
Other than that, keep the interior of the G4 and the fan blades clean, and all will be fine. If you load up with hard drives and PCI cards, then you might think about a higher CFM case fan. Until then, no worries.