Just to clarify and to be sure, my point is mostly about having multiple GPU working at the same time. Dunno why, but it sounds weird to me.
Anyway I won't plug it to USB but to the little PCI while the large one is used for the main GPU.
This would probably only be for mining purpose, I was, as you mention, thinking that mining wouldn't require too intensive transfer speed.
Also, concerning power, I can get powered riser or use my PSU (got multiple, wont be a prob).
Still, you mention a quite expensive hardware, dont you think mine would work?
Thank you all.
If you use the rig only for mining and not for gaming, there is not much requirement for data transfer.