Does that 95% also include the new supported CHD games wich are cpu suckers? On my system I can't even get Cruising USA or World to run at full speed and there not CHD's. I see Carnevil running at 40% if even that. Now Max Force and Area 51 run at full speed on my system.
Sorry to rain on your ideas, but I wouldn't recommend that upgrade. As posted before, if you have a few favorite games that "almost" run on the current system, the upgrade might help.
For Cruisin, etc. try enabling cheats "-cheat" command, and underclocking CPU 0 after the board init and checkout completes.
Aaron Giles estimated that Cruisin and World and Blitz '99, SF rush, etc. will need on the order of a 4Ghz P4 to run properly.
And the Athlon XP is retiring, so no future upgrades. If you're waiting three months anyway, you might see where Athlon64 prices are then. At least that way, you'll get a system that more advanced processors will be produced for and you could just do a processor swap as faster versions are released.