It's not all that similar. There's more emphasis on memory subsystem management on Wii U, with large CPU caches (3MB versus 1 MB in 360) and a large EDRAM on the GPU (32MB versus 10MB on 360) intended to balance out a lower clockspeeds and main RAM bandwidth.  The GPU and CPU are quite different in architecture too; even ignoring the cache differences, the Wii U CPU is out-of-order-execution compared to 360's in-order-execution CPU, while the Wii U GPU is so weird that even after getting detailed pics the tech-heads still can't work it out.

The architecture is very similar actually. Both systems have 3 general purpose PowerPC cores in terms of CPU power. Out-of-order simply means that the CPU can execute commands in a different order than what is written in the code. From the developer's standpoint, no significant changes need to be made to the code, and it makes things faster if anything. More cache and more EDRAM, also dont make things "different", they actually make things easier. If i add another 8 GBs of RAM on my PC, it doesn't "change" the architecture. Regarding the GPU being "weird", I am not sure what you mean. It's an AMD Radeon part, so it can't be all that exotic. And considering its DX11 compatible, it should be a lot easier to program for than the DX9 GPU of the 360.

Of course, nobody claims that you should be able to port the 360 code and things would run faster without any work. But with all things considered, within 12 months from launch, this system should be 100% figured out by developers.

So because they both have 3 CPUs and edram, that means they are similar architectures? And what makes you think WiiU's CPU is general purpose like 360s' when we've been told the CPU is made to run specialized tasks and most of it's work is offloaded to the GPU instead. Unlike PS360 which had pretty strong GPUs compared to their GPUs.

 Like modern gaming PC architecture, all three consoles this generation are much more GPU focused,Wii U included. 

If "from the developer's standpoint, no significant changes need to be made to the code", then WiiU shouldn't have struggled so much at running PS360 ports, yet it was said many times from the beginning that it ran those ports poorly which led many to believe the console was weaker.

From a dev:

" Read the Audiokinetic Wwise release notes from 2012.2 to 2013.1. You'll notice that they report optimizations on Wii U of several hundred percent with each new release, which means parts of their code run at least an order of magnitude faster now compared to back at launch. Optimizations are platform specific, optimizations from the PS3 and 360 versions simply don't translate to Wii U because the hardware is different. They had to start back at square one, "

WiiU is a very custom built part and to say it is similar in architecture to Xbox 360, because  "Both systems have 3 general purpose PowerPC cores in terms of CPU power" is incredibly falwed. So is saying it can't be all that exotic because it's an AMD Rdeon part. If it wasn't all that exotic, then why are people still unable to use the GPU die photo to say what stock GPU it is based on and why are there still part of the die that haven't been figured out yet?

The WiiU isn't the same architecture as Xbox 360. It's very different.

No system is ever "100% figured out by developers" only 6 months from launch. Did the 360 show its full power within 6 months? Did they PS3? No. These things take time. There are fundamental differences between the Wii U and the 360 that negate an instant understanding of the underlying design differences. Everything from the CPU design to the memory architecture to the GPU design is different enough that a multiplatform engine will not be able to extract the extra performance without extensive modification. So far, the only devs that have even TRIED to offer said modification are devs like Frozenbyte and Criterion, devs who have SUCCEEDED in getting more performance out of Wi U than PS3/360 could offer.

Me too. :P

Ugh, I saw the headline and knew imediately that people would take the "several generations" part out of context and run with it...
They were talking about GPU-Generations(modern feature set, DX11 equivalent etc), not console generations -.-*

Let's take things from the start. Technically, CPU architecture refers to the instruction set of a CPU. Examples are, x86, ARM, MIPS etc.

Both the 360 and Wii U use PowerPC architecture. There is no "exotic" architecture involved, like PS3's mixed-core solution. Now obviously, some people want to believe that there is immense untapped power in this system. The cold hard truth is that Nintendo's system is based on 40-45nm silicon and runs at 75 Watts during full blown game-play. 80 dollar video cards from the same process node run at 100-130 watts. If you understand the principles of semi-conductor size and power consumption, then you know what I'm talking about. There is barely any hardware inside that console.

ViktorBKK, yes, WiiU is empty inside and its runned by weird Nintedo magic...

1. It runs at 33 Watt (the power brick is rated at 75 watt max )

2. You are right with the achitecture, but Espresso is still very different: You have two processors with immensely long pipelines and multithreading capabilitys (Xenon´s cores can work on 2 threads at the same time)which are clocked very high (3,2 ghz) and on the other side you have a low clock(1,2 ghz), single thread per core CPU with huge caches  and a tiny pipeline that does more per clock than Xenon and is capable of out of order execution+ a DSP (a seperate core that handles the sound wich often used one thread in X360 games and even one SPE in PS3 games)

The set up is far from "the same"

You just lost all credibility there in my eyes!!! The 360 is limited to DX8.1 at most, trying to artificially boost the system's capability to make the Wii U look bad is a very shameful thing. Naughty boy.