When I saw the title, I assumed this was Intel's way to get into ARM without losing face. But... no. It's Atom. They just won't give up on x86. Sorry Intel, nobody wants it, execpt for the few thousand Win8 tablets getting churned out every month.
You won't have to wait for the Rockchip SoC to get a handle on Silvermont versus ARM on a TSMC 28nm process -- the Intel SoFIA chips already announced and slated for shipment later this year (dual core) and early next year (quad core) will tell the same story. That's why Intel could work this deal with Rockchip -- they already had ported Silvermont to the TSMC process.
If Intel can sell Rockchip SoCs without any "contra-revenue" that will be a big help to Intel's bottom line. Actually, just a little help, since there's not a lot of revenue involved in low-end tablet chips, regardless of what core is inside.
Intel is unlikely to use ARM GPU IP, but Intel's own IP is out of the question for this generation as well given that Intel's major graphics overhauls happen at 14nm (and the current Gen 7 GPU from Intel is very poor).
My guess is that the entire SoFIA lineup, as with the 22nm Merrifield/Moorefield platforms, will use Imagination IP. Intel has experience writing drivers for ImgTec AND Intel is Imagination's largest shareholder.
Well I would like to see an explanation that makes sense. First of all Intel needs to get high volume with these SoCs to make a profit at all. That's not a given since x86 on Android has so far not been very successful, and the low end already has already several highly efficient CPUs (eg. Cortex-A7 and A17) that will compete with Silvermont.
Using 28nm TSMC means most of the profit will now go to TSMC, not to Intel. While the higher volume will offset the lower profits per chip, Intel now has additional costs, both in terms of porting to TSMC 28nm as well as even lower utilization of their 22nm fabs. Still think this is a win-win situation?