Synergistic Processing Elements.
Cell processor has 8 of them, one of them disabled for better yields. 1 reserved by the OS, leaving developers with 6. As said above, they are single precision number crunching little god boxes. much like 3d cards with vertex/shader fragment programs, each SPE has its own standalone program that you send to the SPE (with parameters, ie data or pointer to data) run and pull the result out.. the PPE (Power Processor Element) basically manages the SPE's and the data sent too and recieved from each SPE unit.. the PPE is a almost standard PowerPC processor with SMT (think hyperthreading that existed in pentium 4's on PC).
The annoying side with SPE's is that you have a 256KB limit for obth the SPE program code and its data (shared).. Resistance:fall of man developers developed since nice tricks to combat that limit .. but lets go there another day :)
