I am trying to find the reference at the moment, but don't have much time so don't expect it soon. However I am fairly sure it was both dual-core and low power even, as its power was touted at 15 watts per core.
So no, I don't really buy for a moment that that was a significant factor in Apple switching, they just needed a scapegoat.
Bah nevermind, found a few links...
http://www.news.com/Start-up-plans-n...3-5907281.html
And while I don't consider the Register a good source half the time, they have the basic idea down, though I haven't read the article to see how accurate it actually is.
http://www.theregister.com/2006/05/19/pasemi_apple/
That chip as cited still beats out the Core2Duo in terms of Performance/Watt if memory serves, Apple was in talks with the company.
As I said before, PPC was used as the scapegoat for that. I am not saying it is a bad move, just that people always blame the PPC architecture, but I don't think that was anywhere close to a good reason.
Seablade
Wikipedia, just cause I feel like it
http://en.wikipedia.org/wiki/Power_M..._G5_derivative