Rosetta uses Transitive, says Transitive.
Apple's not commenting, of course. Back in 2001, Transitive showed a 1.4 GHz AMD processor using Transitive's code-morphing technology, which ended up emulating code like a 1 GHz PowerPC (which back then didn't even exist!). Let's assume that they've actually improved their technology and worked quite closely with Apple, and I'd say this gives quite a good picture of what we can expect. I mean: If a 3.6 GHz intel processor emulates a "2.5 GHz G3", this is probably good enough until updated software is released to "know" about the intel processor. Sounds good to me.