I didn't know 3Dfx cards have problems under XP. Its totally crazily overpowered with that system to run 98SE.
It's better to go p4, even on win98SE build anyway:
you can only gain from Pentium III/II
-you can downclock and undervolt p4 to p3 level, to get same speed if needed. But you can go higher in speed if needed. (you can have winXp/win98SE dual boot, and under winXP, you can play more later games)
-you gain USB 2.0 and LAN integrated
-you gain cheaper build in general - prices of p3 are in general higher.
-board is less used, newer, so capacitors are in better shape usually.
-you gain more RAM, although under win98SE only 512 is max, under win XP you can use advantage of 2GB.
win98 can be limited to see only 512MB, so you dont have problems even with 2 GB installed.
-under DOS, you can use moslo.com, to slow down to 286/386/486 level. Later DOS games supports PCI soundblaster like Live! for ISA soundblaster only DOS games (earlier ones), you have strong 2GHz+ CPU to use Dosbox under WinXP - it will handle all earlier DOS games, cause they are not very demanding.
That means you are covered for DOS, win98SE and winXP era till like 2006. On P3 you are limited by eighter 1 Ghz (slot1), or 1.4 ghz (Tualatin). You gain nothing by p3, except you can use 3.3v AGP cards and in some cases ISA soundblaster for earlier DOS games (but it is not needed with Dosbox). But you need then another computer for windows XP era anyway, so with p4 ,you can have 2 in 1.
