AltiVec & Rosetta
From osx86project.org, posted 11/21/2005:
http://www.osx86project.org/index.php?option=com_content&task=view&id=68&Itemid=2
"First, the Rosetta emulation platform in 10.4.3 build 8F1111A has been upgraded to feature full G4 support, including Altivec. This not only adds a new layer of compatibility to Rosetta, but also improved speed for Altivec-equipped applications. This upgrade is reportedly available as a small downloadable update to build 8F1111."
If this is true (no reason to doubt it's not, considering the source is not a rumor site), then all the worries of AltiVec-enhanced applications "sucking" under Rosetta is no longer an issue. Even under emulation, the increased bus speed and processing power of a dual-core Yonah over a single-core G4 should provide more than enough horsepower for older PPC applications during the transition period.
Developers who have their acts together will NOT be relying on Rosetta as a true "solution" anyway...they will do as Apple has asked and update their apps to Universal Binary format. Any major developer who hasn't got Intel-ready builds already working in their labs doesn't have a right to call themselves an Apple developer at all. I'm not talking about projects ready to ship...but they should at least compile and run on Intel right now, today.
So this whole theory that "Apple can't put Intels in PowerBooks because developers need time to upgrade the pro apps" is nonsense. Current G4-compiled pro apps should work quite well under the AltiVec compatible Rosetta update, with Universal Binary updates as needed for those apps that would see significant performance enhancements under a true Intel compile.
I also discount the theory of any chip less than a Yonah making it into any Intel-based Mac. The iBook and PowerBook today use exactly the same processor. Only minor MHz differences separate the two competing notebook lines...with screen size, resolution, video chip, Firewire 800, and PCMCIA slots being other distinguishing features.
Apple could release new iBooks and PowerBooks on the same exact day, BOTH having dual-core Yonah processors, and use the same slight MHz differences and the other hardware distinctions above to keep the lines separate. There is NO need for Apple to intentionally cripple the iBook with a non-Yonah processor. If anything, having Apple's entire notebook line-up going dual-core at the same time is a major publicity win for Apple.