[rbanffy]

> treating the computer as a distributed system

Sure, but where's the fun in that?

Up to GPGPUs, there was no reason to build a machine with multiple CPUs of different architectures except running different OSs on them (such as the Macs, Suns and Unisys mainframes with x86 boards for running Windows side-by-side with a more civilized OS). With GPGPUs you have machines with a set of processors that are good on many things, but not great at SIMD and one that's awesome at SIMD, but sucks for most other things.

And, as I mentioned before, there are lots of ARM machines with 64-bit and ultra-low-power 32-bit cores sharing the same memory map. Also, even x86 variants with different ISA extensions can be treated as different architectures by the OS - Intel had to limit the fast cores of its early asymmetric parts because the low-power cores couldn't do AVX512 and OSs would not support migrating a process to the right core on an invalid instruction fault.