Symmetric Multi Processing
http://en.wikipedia.org/wiki/Symmetric_multiprocessing
basically have two cpus in one tower
originally referring to dual Xeon or Opteron etc workstations and servers
I owned an older Dual Xeon for years and love dual cpu setups
Dont let anybody fool you
if you have a chance at a modern dual CPU setup cheap then go for it
More cores the better
Really expensive and not gaming machines since they dont overclock or usually have SLI/CF etc
but for encoding/rendering/multitasking they cant be beat by anything
if you look at multithreaded benches like Cinebench they are dominated by dual CPU setups
how can you not like the idea of 8 cores/16 threads (or more) with 32gb ram!