It depends greatly on the games you play and the resolutions. For the most part, the Tualatin would be fine for games up to 2001, maybe even 2002 (although it won't be perfect in all extreme situations). Like, for example, in a busy Diablo 2 fight scene you will get stutters/framedrops. 😀
The GeForce 4 Ti 4200 is definitely bottlenecked by the Tualatin. But, again, this is not necessarily a bad thing, it depends on what you play. In certain games the bottleneck will mean that instead of 900 FPS you only get 200 FPS, while in other games the bottleneck can seriously affect performance.

Bottom line: the Tualatin is great for Windows 98, while for XP... not so much. For XP, at the very least you want a late Athlon 64, although a Core 2 Duo would be highly recommended.