One problem this (partially) solves is the performance gap between internal PCIe-based peripherals and external devices. USB3 and ExpressCard both top out at ha

One problem this (partially) solves is the performance gap between internal PCIe-based peripherals and external devices. USB3 and ExpressCard both top out at half the bandwidth of even a single lane PCIe 3.0 slot. If you look at the list of companies contributing blurbs to Intel's Thunderbolt page, about half of them are companies producing high-end A/V peripherals where this makes a real difference in terms of what kind of product they can offer.