I want to preface this with the following: I don’t want to pull a fanboy move here. The only thing I assert is that a recent OS (ie. Ubuntu 10.10) can give a considerable performance improvement (without changing the hardware) compared to an almost 10 year old OS (Windows XP).

Without further ado, compiling a large(ish) Java project on Windows XP:

real    3m16.776s
user    0m2.333s
sys     0m0.796s

And Ubuntu 10.10:

real    1m32.169s
user    2m10.488s
sys     0m12.677s

More than twice as fast! Neat!

Update: a friend just got a newer machine with better processor (Core i5 vs Core Duo) with Windows 7. The new machine with Windows 7 compiles the project in ~1m50s, so still Ubuntu seems to be the better choice.