I was thinking bidirectional ring bus in my model; indeed if it were unidirectional you'd end up with the same result for all CPUs. FWIW, the Cell used a bidir

I was thinking bidirectional ring bus in my model; indeed if it were unidirectional you'd end up with the same result for all CPUs. FWIW, the Cell used a bidirectional ring bus network, and it's of the same generation and happens to share technology heritage with the XCPU... (very similar PowerPC core) :-)