I had a quad 2.5GHz water cooled Mac Pro on my desk, and the OG Intel mac pro, as well as Apple's dev system. I can tell you with 100% certainty, that Google Earth ran faster on the Intel Mac Pro under Rosetta than natively on the PPC Mac Pro, as I'm the person who ported it. When I had the native version working on Intel, that was the fastest of all, by far.