Uh oh... some mis-information. Athlon MP processors are NOT exactly the same as Athlon XP's. Athlon MP's have an L3 cache added onto them for communication between processors in a multi-processor setup so that one processor can access the data in the other's processor's cache. I'm not exaclty sure how it would effect performance in a single processor rig... but I do know that Athlon MP's go through more stringent testing at AMD to ensure complete stability and reliability in server applications. That MAY translate into a chip that can overclock higher, or can be overclocked to the same speed with less voltage, thus running cooler. If you can afford the extra cash it costs, don't worry about it... it will work fine, possibly even better than an XP2800. I have a friend who has a Palomino MP1900 running at 1.8 Ghz I believe at stock voltage. Quite an overclock for a Palomino core... especially not one of the popular steppings that people were using... I think the XP1600 Palomino's had a certain stepping that could hit 1.8 and even 2.0 on water. But anyway... use your MP... run some benchmarks at least if you're going to return it... then compare to an XP2800 replacement =)