2 USB 3.0 ports to connect internally and 2 usb 3.0 ports to connect two external ports. No problem, everything works to perfection itself whether to bring out the cable to plug in the back, 2 external ports. I associated with "PEXUSB3S2E2I StarTech.com USB 3.0 PCI Express Card" without worry. By cons, with the "Adapter StarTech.com BRACKETFDBK" fairly thick plastic in fact, the introduction of screws proved a "hair" too short. I reserve the right screws which allowed me to immediate implementation. The closed case, it is as if it had always been there ...