Unless you have a really, really old system with <1GB RAM, Win 7 will probably feel faster thanks to Superfetch caching commonly used programs. I think some older games perform better in XP, but newer ones designed for Win 7 will work better in it. Win 7 has much better task scheduling and will work much better with multicore (especially >2 core) CPUs. I mean it's really not a fair comparison for XP, Win 7 has nearly 10 years of development on it, will obviously work better with newer hardware. Win 7 does use a bit more resources (more so if you're running 64-bit), but it's not enough to worry about, the features and overall performance you gain is more than worth it.