Steve,
You've posted this in the ATI group so I guess you're gonna get more
answers saying go for the 9800pro. BUT, briefly, here's my 2c.
*The GeFX5900 actually renders a PCI slot unsuable due to its massive
heatsink - which sucks if you're low on space. It's big, it's heavy,
it's power hungry and it's noisey. In comparison, the 9800Pro is
almost silent and takes up one slot (and I know cos I have one).
*The 9800pro just seems to slightly outperform the GeFX5900. Not
always, but I'd say it's 80-20 in ATI's favour. The difference,
though, is probably barely noticeable - but it's nice to know you've
got the faster card!
*Ever since the benchmark 'cheating' scandal a year ago (in which both
nVidia and ATI were involved, but nVidia looked a lot worse), I've
lost a bit of respect for nVidia. The Radeon cards seem to achieve
their speed due to smart decisions made by ATI (e.g. 256bit memory bus
- originally nVidia's 5800's memory bus was only 128 bit wide, and it
was a shocking card. I reckon they included this in their revamped
5900 to 'keep up' with ATI). I just think nVidia try to keep up with
ATI's 'smarts' by just pumping their card more MHz and more power.
And sure that may work most of the time, but there are tradeoffs (the
worst of which is noisey cooling).
And that was my thinking as to why I went ATI.
Cheers,
Simon