Its never nessecary. However, it does have its advantages provide the programs you use are written to take advantage of two processors. DOS and Win9x can absolutely not take advantage of SMP, however.
SMP is also quite good for multitasking. Sure there are a few programs that are faster with SMP, but for the most part the gain is very niche and very minimal. It's much more impressive to say that I can encode two movies at the same time, for example.
MD-2389 wrote:Bubba: You forgot to list the Athlon MP.
modified XPs as well, P2's and P3's PPros etc...
so what, he said: "include" meaning a cross-section of what is available. Not a statement meant to be all inclusive.