make my xp 2200+ to be an actual 2200+?

i am running windows 2000 pro, and i checked the speed of my cpu in system management, but it only clocked in at 1808 the first time and then 1809 the second time… it is an AMD ATHLON XP 2200+, now how can i get my 2200+ to be as fast as a 2.2 or if not that high, any higher then 1800??? will i have to use windows xp? i know the clock speed on the box says 1.8 but i thought XPs could go higher than that? please let me know, thanks in advance