Since this already getting confusing, how does this sound:
MPI: Mac Pro PowerPC version
MPII: Mac Pro Intel Clovertown
MPIII: Mac Pro Intel Penryn
Yes? No? Maybe? Tought about using regular numerals compared to Roman, but MP3 would be even more confusing and besides, Apple has some history using II and III...
MPI: Mac Pro PowerPC version
MPII: Mac Pro Intel Clovertown
MPIII: Mac Pro Intel Penryn
Yes? No? Maybe? Tought about using regular numerals compared to Roman, but MP3 would be even more confusing and besides, Apple has some history using II and III...