You can connect a USB 3.0 if your motherboard supports USB 3.0. SATA 2 will work in the same speed. The USB 3.0 will lower its speed to match the speed of SATA 2. So even if you connect USB 3.0 devices you can't expect more speed.
You can connect a USB 3.0 if your motherboard supports USB 3.0. SATA 2 will work in the same speed. The USB 3.0 will lower its speed to match the speed of SATA 2. So even if you connect USB 3.0 devices you can't expect more speed.