Question about compat with xp 2800+ with pc2100

I'm thinking of replacing my mobo/cpu and upgrade from xp 1700 to xp 2800, is it feasible to use pc2100 ram on that processor? am i able to? I'm kind of tight on money and if its possible i'll stick with that for another week until i have more money and can order a stick of 3200

Yea that config will work. You will just need to adjust the memory:fsb ratio to 5:4 or 80%.