The first few sets of intel chips in apple computers (macbooks, imacs, mini etc.) I believe are 32-bit processors. All recent PPC processors are 64 bit. This means that technically, if you were running 64-bit app on Leopard with two computers with identical hardware except for the processor, then the PPC architecture would suited for better performance.
Now, whether or not the PPC is so far behind in evolution that it cannot keep up with the first wave of intel chips even though they are only 32-bit remains to be seen. My assumption is that the later model G4's (1.5+) on the powerbooks and the G5's will run most 64-bit apps faster than the first set of Intel processors dual cores in the Macbooks and Mac Minis since they are 32-bit.
Anyone can correct me if I have stated incorrect information here. Keep in mind that most of my post is speculation based only on 64-bit PPC vs. 32-bit Intel Dual Core.
I love that quote.
It depends on how the applications are optimized. If they're optimized for 64-bit, then yes, an application running in 64-bit on a PPC machine could theoretically be faster than that same application, running on a 32-bit Intel machine. But when you start to talk about applications that are multi-threaded (can take advantage of multiprocessors) and you make that comparison, it doesn't hold any water unless you're talking about a dual G5 system.
All things considered, it's a difficult comparison to make with so many variables - and of course, when we start to talk about C2D systems, it's pretty much irrelevant. What's really interesting is that the CD processor
really is a 64-bit chip, it's just that the 64-bit extensions are disabled.
Oh, and that quote isn't a statement of opinion - being a 100% RISC, clean sheet design, the PPC platform is inherently superior. Had it had the benefit of the development focus expended on it that the x86 platform did, it would probably be miles ahead of x86 at this point in time.