PCIe. Not openSuse specific, I hope not OT

As in the subject this is a general hardware question…
I have purchased a PCIe card to give me USB3.0. Unfortunately, it uses a PCIe X4 interface. I have only a PCIe 1x slot available. If I buy a PCIe x1 > PCIe x4 converter/riser (widely available) How much bandwidth do I lose?. And will I care?

This is what I have bought:
http://www.silverstonetek.com/product.php?pid=498&area=en

And this my Mainboard:

http://www.asrock.com/mb/AMD/960GC-GS%20FX/

And I am considering using one of these:

http://www.ebay.co.uk/itm/PCI-E-Express-x1-to-x16-Adapter-Extender-Cable-Riser-Card-Mining-Cooling-bitcoin-/231208101508?hash=item35d513a684:g:-2MAAOxylpNTUlNG

Now the extender contains a “USB 3” header and cable. I guess this is just a way of passing the connectors to the board, using cheap of-the-shelf components… But is it? I could not use it as a USB port could I?