If you are just running one and have at least 1 PCIe x4 (x8 or x16) slot you can try this. (I am running it on Windows 8.1 Pro. in a x16 slot.)  Two will not fit due to the width of the circuit board, but it is doing 2A to the USB slot. It says it will do 2A to each USB slot.

https://www.amazon.com/gp/product/B010PNUALA/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

I average about 4,394 kH/s at 798 setting.