Sunday, November 13, 2005

Cell Microprocessor.

A lot has been said about the Cell chip from the big dogs IBM, Sony and Toshiba. And I'm not going to say anything new, but if you haven't heard or read anything about it this is a quick run down.

If you don't know, it's the new chip for the Playstation 3 and it's about as unique as they come. It's a interesting multi-core CPU but not really in the regular sense (think, AMD and Intel). It has a general purpose "controller" core based on the Power architecture (used in Apple machines) called the PPE (Power Processor Element). Additionally, it has eight SPE's (Synergistic Processing Elements) these are "simple" specialized CPU's that do the bulk of the work. They do the work in succession. One will finish and move the product along to the next SPE and so on. Both the PPE and each SPE have their own caches also. And according to IBM the CPU will be running at 4Ghz!

Connecting the CPU to the memory is the new Rambus XDRcontroller (memory bus) and FlexIO (system bus) interconnects that will provide over 25 and 76 GB/s of bandwidth respectively.

Thats a lot processor and IO... Consider the benefits for Playstation type uses of this processor. Graphics are floating point calculations. The floating point ability on this CPU will be huge. It will be much like the video cards used in todays gaming computers but multi-core and less specific (not just used for graphics). In the end it should be a nice blend of specific use and generic processing that should make the PS3 pretty awesome.

Needless to say this going to be a sweet architecture. I think we will see more of a trend to this style of design in porcessors. Moving away from the single core, monolithic style processors we all use today. To single processor multi-core chips that have cheap and easy "co-processor" cores controlled by a one multi-use core. Spreading the load among more CPU's is the name of the game. We are already seeing this happening in both the Intel and AMD camps. The Pentium D and the Athlon X2 are the beginnings of what will be a big change in CPU's.

Moreover, I think we will also see a trend toward more specialized CPU's, ones that are made for a specific purpose or at least that can handle generic use but have a specific slant to them.

For instance, 5 years from now when you buy a PC to connect to your TV and home stereo that machine will have a CPU honed to that sort of purpose. Instead of the CPU being completely generic and avgerage at everything, including stuff you won't be using it with, it will have a job it is really good at and below avgerage on everything else. Why use a Swiss Army knife to cut a tree down when you could use a chainsaw. Other than the performace advantages, a driving force to this style of CPU design is the cost. It is finially getting to the point where is it affordable to manufacture single or similar use CPU's.

Regardless of what I think, the new Playstation is using the CPU and I looks to be if nothing else a pretty interesting design.

"But you don't have to take my word for it." ~Reading Rainbow

More info:

ArsTechnica Part #1
ArsTechnica Part #2
IBM Journal Research and Development


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