Until recently, Athlon XP and Athlon MP processors aimed at different market segments differed only by the price. Athlon MP processors intended for use in dual-processor servers and workstations now feature absolutely the same architecture as Athlon XP CPUs used in desktop systems. Moreover, it is simply impossible to distinguish between Athlon XP and Athlon MP via software, when they are already installed into the mainboard. Nevertheless, Athlon MP processors are selling at $50 higher price than Athlon XP with the same core clock.
As a result, there appeared a tendency, when most users started using Athlon XP processors in their dual-Socket A systems instead of the Athlon MP, or even Duron CPUs, which work in dual-processor configurations very well, although they are targeted for the value market. Of course, AMD, which is certainly getting lower revenues in the server market, is not happy about this situation. That is why, as this Ukrainian site reports, AMD is going to deprive its non-server Athlon XP and Duron CPUs of the possibility to work in dual-processor configurations on the hardware level. The thing is supposed to happen when Athlon XP and Duron families shift to new 0.13micron Thoroughbred and Appaloosa cores.