Difference between AMD MP and XP

Overall they're the same, except the MP chips are top grade, well tested chips, so not to disappoint someone building a server, etc. Current XP's are much faster and some use faster buses, which overall increase system performance and MP chips are a few grades behind due to the fact they need to be well tested before release, etc. Two cores are better than one though, so basically two Athlon MPs will l be better than one XP, especially for multitasking purposes. But if used alone, there wouldn't any difference, except for the testing.