If using Windows 7, just run the Device Manager or System info app from control panel.
As for the difference, IB is about 5% faster on average than SB at the same clock frequency although for some things like encoding it can be much faster as it uses QuickSync 2 vs. the original QuickSync (1.0). Plus its onboard iGPU is about 60% faster as well, it uses PCIe 3.0 and USB 3.0 natively, etc.