You have presented a well reasonsed response. From my perspective, as state in other threads SOC technology has a lot to offer Apple. I just have trouble with the idea that the current 440 would step into a main CPU role well.
So considering die size shrinks and the design effort already put into the 603 series, I would have to think that this would have more likly hood of working its way into a SOC system. The other alternative, as you mentioned, is the 300 series. The 300's could very well be a new and clean design that would lend itself very well to described usages.
While Apple has done a huge amount of work to make much of OS/X SMP aware, there is probally alot more they could do. So any system based on the 440 series would have a big performance delta. That is application performance would be all over the map. On the ohter hand it could be argued that Apple is further ahead on delivering SMP aware systems than any other mainstream vendor.
I like the thought that Apple would have the brass to do such a machine, but I don't think they would deliver such a machine on their flagship laptop. I'd geuss a IBook myself or even a iMac. Further it will be a SOC system and not a traditional MCM, for no other reason than the expense.
The original poster is certianly creative in his responses. As such some of the responders suggesting that the thread be closed should be a little more opened minded. We are likely to see such systems sooner or later, I know that Intel has worked on such designs or concepts. Well Intel has left out the SMP part, probally so they can keep their sick marketing practices.
Originally posted by Amorph
OK, let's step back and look at this. If it helps, don't think of it as a PowerBook, just an engineering exercize.
By itself, the 440 series is nothing to write home about. 4 of them, however, with four AltiVec units and FPUs, offer some real potential. They're very low power. The purpose of the MCM design is to get really high throughput between the chips in the module, so bandwidth and latency within the MCMs should be very high and very low, respectively. This is critical for clustering / massive SMP.
Now, consider the independent source that offered that IBM and Apple were developing a portable CPU from the 300 series, not the 900 series. What's the 300 series? Well, let's say that the chips in its family look a lot like the 440, and nothing like the 970.
Consider also that IBM is currently building a supercomputer that will utterly crush the current #1 out of PowerPC 440s.
Consider Cell, the IBM project to build a platform on massively parallel solutions for the first time (massive parallelism is nothing new, but each implementation has been a custom job with custom code, not really a platform). The above-mentioned supercomputer will be made of 128 nodes, each with 1,024 CPUs.
Now, we're talking about 4 cores, 4 AltiVec units, previously unheard-of bandwidth and latency between CPUs (on MCMs) - all requiring maybe 8 watts? They can easily grow into a 64-bit variant, since the PowerPC spec is natively 64 bit.
This is a highly unconventional platform for a personal computer, but I feel compelled to point something out that I haven't in a while: The only remaining champion of the traditional personal computer architecture is Intel. Everyone else is taking advantage of technologies like HyperTransport that allow for workstation-like motherboard designs at PC prices. These architectures are built around lots of bandwidth, which deëmphasizes the need for one single powerful CPU. OS X can already do MP. Apple is already working on software for clustering. You can run this setup as a small cluster with wonderful gobs of bandwidth and negligible latency, and it will run very well indeed.
This, to me, is a far more interesting rumor than the 970 was - the 970 was exciting, and more than welcome, but it's fundamentally conventional: Big, fast, hot. This sort of 440-based board is one of the mammals scurrying around under the feet of the mighty dinosaurs.
As to whether the PowerBook is ready for this, that's an interesting question. Multiple low-power processors are better at doing multiple tasks at once than they are at doing one big task (unless of course that big task is split up into lots of little ones behind the scenes) - c.f. the dual-processor iPod. So, if you can imagine something that will need to run some fairly compute-intensive services regularly while maintaining a responsive interface and doing light-to-medium work, that would do nicely. (OS X is already moving this way, using the GPU to run QE, and that's only the beginning of what they could do.) The main obstacle here is the programming paradigm implied by this architecture, which most current software (and most current languages) are ill-suited to. This might have the raw theoretical power to replace a single fast CPU, but it might be a while before software that can exploit it is widespread.