He already has USB3.0, but USB3.1 is only Type C I think.
It's possible he's referring to the "Type C" connector instead?
The motherboard chip is designed to communicate within the limits of what USB3 (normal) offers so I'm not aware of a different cable for... type C?
So please CLARIFY what it is you are asking.
Also, please not that you can already get approaching 600MBps via USB3.0 front headers and that there are very few devices that can saturate that. Possibly a Type C SSD.