on newegg an athlon xp 1.8ghz costs 83 dollars, a p3 1ghz costs 87 (both OEM), both can run in dual configuration... the athlon has 512kb l2 cache, and much higher clock speed/performance... so if you do decide to go multi-processor check them out, ive seen benches showing 2 athlon 2100+ beating dual xeon 2ghz, at half the cost... and as for the performance boost for dual processor, it is not in any games i know of(quake 3 was supposed to support it but no benchmarkers or users have been able to enable it without massive errors arrising)... so truthfully until games come out that support it, or unless you are running a server then stick with single processor.
windows xp pro can run on a 300mhz processor, and shows no lag past a 1ghz processor, so unless you want to have a computer that can maximize and minimize your documents folder faster than anyone else, id say stick with single
windows xp pro can run on a 300mhz processor, and shows no lag past a 1ghz processor, so unless you want to have a computer that can maximize and minimize your documents folder faster than anyone else, id say stick with single