That's immaterial since, whatever the underlying CPU architecture, the 3DS chipset is a custom SoC. They don't get the economies of scale of something like the generic Chinese quad core ARM chips being bought by dozens of companies for various no-name tablets and phones, or even a Snapdragon 801 which is powering basically every high end Android phone model introduced this year.
Not that it matters much since the 3DS SoC is very small and using an older fabrication process with very low target clocks so it is a very inexpensive part at this point.
Do we know who fabs the 3DS SoC? It's only Nintendo's name on the heat shield. Anyway, considering the time frame, higher CPU clock, and most importantly, additional VRAM, I'd be willing to bet that the new 3DS got a die shrink. 28nm is quite mature now...
My hunch is this is their primary idea: To introduce the core NintendOS platform with the New3DS. It will run full retail 3DS and n3DS without the need for having specific architecture or graphics chip (such as PICA) to run the games, and thus they can "let go" of their previous legacy support without having to drop backward compatibility.
Unless they've drastically upgraded the internals, I don't think they can afford the performance to add in an abstraction layer like that. I can imagine it will be quite difficult to implement when the games are coded for the specific hardware, which is why I think their next handheld will just have the 3DS hardware (or important portions of it) included.
I know, and I get why they do it, 100% compatibility is very important for them and they do it by the book. Which is why I don't think they did away with ARM11's on the n3DS.
But since they end up being the last using whatever processor platform they're relying on I personally don't get why they didn't go with Cortex A8 instead when they did the 3DS, A9 was out but nevermind that, it would be a modern architecture compared to ARM11, they had to know they were locking themselves down onto a worse CPU because of a few bucks.
Yeah, the ARM11s were a letdown, although Apple were selling the iPhone 3G up until only the year before the 3DS launch, so it wasn't entirely ancient. The Cortex-A8 didn't support multiprocessing, was a larger core, and drew more power. And cost, of course. On top of this, they needed to factor in the ARM946 core for DS BC. So there were some reasons they likely opted against the Cortex series.
