I/O port flexibility

Hi all.

Im looking for accurate information about I/O port flexibility claim under the Lynx Point chipset.

What is it exactly? how does it work?

I have been reading all info availible, and web, with out find a better information than" As the feature suggests, it should give users the ability to allocate which ports are USB 3.0 and which are USB 2.0"

Thanks on advance.