It's X86-64... Sony confirmed that.

Anyway the official released specs found in Sony docs.

Not really a need for an i7 type CPU... you're not going to be ripping up photoshop while rendering HD 1080p videos, building 3D models on another software and watching porn at the same time. What's the specs of that second CPU? I'm sure it's very basic, but I can guarantee party chat, browsing the internet mid game, listening to music. These are a given.

The thing is that with Brazos(Jaguar's predecessor) even the low-end integrated gpu is sometimes limited by the cpu. What do you think will happen with the HD7850 or equal gpu the PS4 has? Also GDDR5 has so much bandwith for system memory, i really have doubts if this cpu will even be able to utilize it.

Just to clarify a few things here:

The Jaguar has a 40bit addressing space, not a 64bit space, so you could clip about half a terabyte of ram onto any Jaguar chip (that is quite a lot more than 8G)

The 64bit is the "data size", simplified the cpu can process 64bit variables "in one swing".

May be. According to people who claim to be in the know at Gaf the Durango CPU will be more powerful, perhaps twice as powerful. And if you look at the leaks from VGleaks, they say the Durango will be x64. They don't say anything about Jaguar. Who the hell knows.

I'm sure AMD and Sony along with their mass collection of developers know that it's fine and it works. Look at the Killzone gameplay, it's going to work, they do devkits prior to debut.

Nowadays virtually every processor does 64-bit registers including Jaguar.

x64 is just a fancy name for an x86 doing something that has been around for 10 years. 

Mate I think your lost. The difference between a pc and an gaming console in terms of optimising is HUGE. THink about it the ps3 only has 256mb of ram imagine a pc with that.