I will explain some basics. This is rough estimations.
Inside any cpu or digital device is transistors which make all the logic happen, generally the more transistor you can fit into a cpu the more performance it has provided you do it logically. Transistors at any fabrication process are spread out in such that you can only fit so many transistor in an area, this is called transistor density of cpu. The Wii U cpu use a 45nm fabrication process very simular to the way the cpu in the 360 slim is made. The smaller the process the more transistors you can fit into the same area. Current intel cpus are made using a 22nm process. Moore's Law allows has show that performance increases almost linear with the number of transistor you can put in.
The Wii U cpu is 32.76mm^2 as measured by anandtech, the xbox 360 cpu is about 88 mm^2 now using the same process as the Wii U, so transistor density should be about the same. The 360's cpu is 2.7 times the size of the Wii U's, meaning there is probably more than 2x the transistors inside the 360's cpu than the Wii U. This does not mean that the Wii U's cpu is only 50% the performance of the xbox 360 but it gives a good indication that the performance is significantly less. This estimate is probably off by as much as 50% but even then it would put the cpu less powerful than the 360's. So the performance of the Wii U's cpu when doing general processing tasks and doing AI, physics and memory accessing will be slower. I would probably think the Wii U's cpu is only about 80% of the performance as the 360 in gaming. This makes it very hard to port a game without a lot of work, the good thing is the cpu isn't the limiting factor inside the 360 most of the time so it won't show up too much if the developers are porting well.
The GPU inside the Wii U is about 2x as fast as the 360. This will allow Wii U to do games at almost 2x the graphics details. GPGPU can't be easily added to existing game engines. It is very different than coding for just a cpu and gpu, it will take some time to get used to. The 360 also has gpgpu functions. This will not solve all the processing limitations in the long run.
Overall the balance isn't great, Nintindo's console will probably be able to play current gen games but just that. With the next generation of consoles, the Wii U will be like the Wii. I wouldn't be surprised if an Wii U emulator be made by the time the nextbox and ps4 come out for the PC.
These are all my estimates and from my experience as a person with a little cpu design experience. The overall result shouldn't be too far off but can still have a pretty large margine of error as nintendo is keeping all the detail secrete.
THANK YOU. I actually GAVE somebody the cpu size and transistor density information yrsterday hoping they had the knowledge to make a decent argument with it, and they COMPLETELY ignored it, and continued circle jerking baseless hearsay.
Nintendos not keeping TOO many secrets this time. And what little they are was given away a long time ago by partners like ibm.
So, we KNOW Nintendos cpu is transistor starved because of its size right? Physics dictate you can only have so many objects of the same size in a given space. So HOW are devs who are actually MAKING wii u games getting the cpu performamce out of the system that they are? Seriously, look at wonderful 101, that is a LOT. Nano assault is only using one core, and has thousands of simultaneous characters and objects on screen simultaneously. HOW?
Clock speed and even cores is no longer the main impediment to performance, (thanks to amdahl, we cant really do much more no matter HOW many cores we add) ram latency is.
The wii u cpu has embedded ram. But not just any embedded ram, as shown in ibm's original press release, uses ibm's newest embedded ram technology. NO Its not l3, thats something else. Its the l1.
http://www-03.ibm.co...lease/34683.wss
' The all-new, Power-based microprocessor will
pack some of IBM's most advanced technology
into an energy-saving silicon package that will
power Nintendo's brand new entertainment
experience for consumers worldwide. IBM's
unique embedded DRAM, for example'
Anybody can make edram. Only ibm can license this stuff. Its edram thats bussed six ways each cell, meaning each cell performs like six transistor sram (6tsram, remember cubes blazing fast 1tsram back in the day? Yeah, 6tsram. Its the technology that made power 7 possible. Power 7 only has HALF the transistors as i7, yet it doesnt just fompete with i7, it beats it. This edram is the reason why. It allows the transistors to effectively perform as over 2x their number. Power 7 only has 1.2 billion transistors (only, lol) However the unique edram allows it the equivilant performance of a 2.7 billion transistor chip. THATS how Nintendo managed such a small cpu.
Read it from the official power 7 documentation I have attached that details ibm's (then) new unique edram technology.