Generally you can get about the same amount done as two separate computers. Sometimes they're a little bit slower since you have two cpu's sharing the same ram, but for the most part it's worth it for the space savings, and extra hardware - i.e. another case, power supply, mobo, ram, video, etc etc. As far as AMD versus intel right now, if money is no concern get a dual 2.4GHz xeon prestonia setup and you can run 4 clients at the same time and probably pop out 4 work units every 4-4.5 hours. Otherwise get a dual MP system, and you can turn out 2 units about once every 4 hours (depending on speed) My dual XP 2000 system on an asus a7m266D takes about 3:45-4:15 per unit.