We can take for granted that the GPU is an R700* variant, this is no surprise and nothing new. But we seem to have confirmation of the CPU inside it which is of importance.
Welcome... POWER7.
POWER7 is a CPU architecture that is remniscent of the Cell, in that it uses multiple processing cores, but this is where similarities end.
The 'minimum' tech specs for a POWER7 architecture CPU is 4 cores at 3 GHz. There are also configurations with 6 processors at 3.7 GHz each and 8 cores at 3.55 GHz each.
The interesting stuff comes here:
Each core can do many separate executions at once.
4 SMT threads per core
12 execution units per core:
2 fixed-point units
2 load/store units
4 double-precision floating-point units
1 vector unit supporting VSX
1 decimal floating-point unit
1 branch unit
1 condition register unit
32+32 kB L1 instruction and data cache (per core)
256 kB L2 Cache (per core)
4 MB L3 cache per core with maximum up to 32MB supported. (I think it is more realistic to expect the lower value of 4MB L3 cache per core for Wii U)
Which means that the CPU inside the Wii U is substantially more advanced than the Cell and the Xenon.
Even if the Wii U has the 'worst' version of the POWER7 CPU (4 cores at 3GHz), then we are still looking at almost double the power of the PS3. And this is the worst case scenario.
I also think that all scenarios lead to the 1.5 GB of RAM being true. Whether it is unified, or somehow split between the GPU and CPU is unknown.
* It might be the case that GPU is not finalized yet. Perhaps developers currently worked with an R700 until Nintendo decides what they will go with. This could also explain the discrepancies between different reports: Some said 'on par with 360', others claimed 3 cores at 3.6 GhZ, others claimed 4 cores, etc. Therefore, it seems entirely likely that Nintendo only gave out 'rough spec' recommendations to developers, and they developed tech demos on PCs (without actual Wii U hardware on hand).
NOTE: My own prediction is a hybrid variant of the POWER7 architecture using a SoC technology to host a 4 core CPU running at 3.6 GhZ per core, and also including an ARM-9 controller CPU (to handle I/O functions as well as take over some of the Wii Starlet architecture formalities). The Starlet on Wii was clocked at 243 MhZ. This one could be clocked to double the speed.
