HP Shows Off PA-8800 SMP-On-A-Chip CPU Plans
Eric^2 writes: "At last week's MicroProcessor Forum, HP's David J. C. Johnson unveiled the details of HP's latest RISC processor destined to redefine performance in Server-Class processors. Following a relatively simple strategy, the PA-8800 processor combines two PA-8700 cores on a single chip to enable symmetric multiprocessing (SMP) on a single processor. Aside from bumping the core speed up to an initial 1 GHz, enhancements include the addition of combined 35 MB L1+L2 cache. The article contains the full text. AMD, please steal an idea..."
...a 1 GHZ processor may not sound like much, even in this dual-core configuration, but keep in mind that this is a RISC processor. None of that Super-mega-ultra-long-50-bazillion-stage pipeline crap that Intel uses to pump up their MHz rating. The article kind of sells this point a little bit short. The RISC architecture allows this processor to do roughly twice as much work in the same amount of time - or, to put it in a more concrete scenario: imagine a pair of 2GHz Pentium 4's running in SMP configuration.
Now that's FAST .
AIUI, there are two competing methods of scaling CPUs now - Symmetric Multi-threading (SMT), and Chip-level Multi Processing (CMP). HP is going CMP because SMT is too difficult in terms of writing the compilers. Both Compaq (with the Alpha CPU) and IBM (PowerX) are going SMT. In fact, the biggest thing Intel got out of it's purchase of Alpha technology, other than the engineers themselves, is the Alpha SMT work.