I'm building myself a another server I already have a 2000 server domain controller that also serves as a database server. I'm thinking of adding a system to act as a proxy sever running Microsoft ISA or either an exchange e-mail server . Can't decide if I should use a duron or athlon xp. The machine will also have about 512 to 768 ddr 2100 and a 18 gig 10000 rpm scsi with a adaptec 19160 scsi controller. So what do you guys think duron or athlon xp.