hello,
I just install a pentium IV 2.0Ghz yesterday in a new Asus P4S533 + a 512 megs of DDR 333 and all is working nice. No need to reinstall XP, just a repair option.
The Pentium IV 2.0 GHZ cost $310 cdn here and a Pentium IV 2.4 GHZ cost $800 ! Really a big difference to have a FSB of 533