Except that makes zero difference if Microsoft is only buying the design/rights to produce the chip like they did with the Xbox 360.
Then they will ask for AMD for a hand in shrinking down the fabrication later on in the consoles life.

But otherwise Microsoft will produce the actual chips at Samsung or Global Foundries or even TSMC.
Global Foundries have no plants in China, TSMC is pretty much all in Taiwan and Samsung is in Korea and the USA.
The actual Assembly of the consoles will more than likely happen in China after the parts have been produced and shipped to that location from all around the world, which happens often with consumer electronics.

Something Microsoft learned quickly with the origional Xbox is that it's very hard to drop the costs of the chips if another company is in control of the whole process who also wants a profit on top of it, with the Xbox 360 they ended up cutting the middlemen out (I.E. Intel and nVidia) to reduce costs massively.

No. 384bit doesn't mean 6 or 12gb.
The biggest consequence of deviating from a power-of-two memory bus is that under normal situations you don't get an even memory amount like 8gb.
However, it's not the only way to get 8gb of memory whilst retaining a 384bit memory bus...
You see, you don't usually have a single memory controller in devices like consoles and PC's, but multiple.
So say if Microsoft dropped in 3 memory controllers, 2 memory controllers could be talking to 2x 1Gb chips each, whilst the 3rd memory controller could be talking to 2x 2gb chips. - Aka. They end up with 8gb of memory on a 384bit bus.
Of course each memory controller would be 128bit (64bit x2.) for a total of 384bit.

Actually i don't understand why you focus on Manufacturing part but not R&D

And even if we only talk about Manufacturing,samsung and TSM have Manufacturing Facility in China

It's GPU bus width

It's because the R&D has been done. It's been done for years, it's PC technology, they will just modify it a little.
You don't honestly think they spend years and Millions/Billions designing a new GPU from the ground up when the consoles competing platform aka, the PC  already has had superior alternatives for almost a decade?

Yes, TSMC has a fabrication plant in China. One plant.
Microsoft will use many.

Well,they're

And what's the point of R&D has been done or not?of course it need to already done,unless MS delay it to 2014.

On a console. It's the same thing, the CPU and GPU generally shares the same memory pool.

So. You are saying that Microsoft grabbed a Desktop GPU, sat on it for years spent Billions and came out with the exact same GPU? Just integrated with a CPU and eDRAM on the same die? Seriously? Try being a little more logical in your baseless arguments please.

And?why would MS think about that?possible doesn't mean they will

One of their RAM plan even crazier than 4GB GDDR5,if they don't use GDDR5 that means it's a lot more than 8GB DDR3