I'm trying to upgrade my 98SE to XP and used the XP Upgrade Advisor and it says that my Nividia Geforce 3 Ti 200 is not able to run XP without more files. I went into "Full Details" and they recommend a possible solution is to upgrade to Windows 2000 first and then try the Upgrade Advisor again.
Unfortunately I can find a Windows 2000 Upgrade Advisor to check for compatibility issues.
A 1.6 ghz Pentium 4 with 512mb RAM and a GeForce 3 card will run XP no problem at all. You might find its a tad slower than 98 was but thats all. I don't see why the graphics card would have any problem with XP as theres XP drivers for all the Nvidia cards.