I think they are engineered in such a way that is optimum performance with servers, I'm not sure how they would do on a desktop system, I imagine they are better at sending data to many users at once, and calculating as many things as possible, quickly as possible. It may not be good on a desktop PC because usually servers run specific programs to host, e.g. Counter-Strike server, which is different to playing the game.
Asus A7N8X Deluxe - Rev 2.0 - Bios Ver. 1007
AMD Athlon XP-M 2200+ - @ 11x188 = 2Ghz (1.75Vcore)
ATi Radeon 9700 Pro (Almost as good as my old 5950U!)
Corsair 512MB XMS TwinX Low Latency DDR 400 - @ 188Mhz
3dmark03 Score: 5086