There are some similarities. One relevant difference is that the GreenArrays GA144 has 144 CPUs on one chip, not just 48. Another relevant difference is that the GA144 uses up to 200 milliwatts, not up to 125 watts. A third relevant difference is that the Intel chip can run existing software, while the GreenArrays chip needs software to be written specially for it. In large part, this is because the Intel chip has 296 kilobytes of RAM per core, while the GA144 has 64 18-bit words of RAM per core (1152 bits, 144 bytes).

The communications infrastructure is also different. The cores on the GA144 are directly coupled to adjacent cores on the chip, so if you want to route messages, you need to devote some of your cores to routing. The Intel chip instead has a router attached to each pair of cores.

I don't think you'll ever see Go running on an F18A core like the GA144's. But maybe that's okay, because you can run several hundred F18A cores for the same power and silicon real-estate budget as a single IA-32 core.

This paper is the best information I've seen on the SCC.