The P55-UD7 builds on the feature set of the -UD6 former flagship. The new UD7 is even more feature-laden than its predecessor, including a 24-phase voltage regulator design, comprehensive memory overclocking (Gigabyte claims DDR3-2600+ speeds), automatic phase switching for chipset, memory, and CPU circuitry, and all the "dual" items, like DualBIOS and dual gigabit Ethernet.
However, the UD7's key selling points are its PLX switch for on-board devices and Nvidia's nForce 200 bridge. The latter introduces additional PCI Express 2.0 lanes, multiplexed from the processor's 16 host lanes.
As a result, both the USB 3.0 controller and the SATA 3.0 chip—again, NEC's µPD720200 and Marvell's SE9128—can utilize PCI Express bandwidth dynamically. The PLX chip is located below the water block of the hybrid cooling solution and provides PCI Express switching as needed. Although the overall throughput problem isn't solved (the LGA 1156 platform still only provides 16 total PCIe 2.0 lanes), this is the best way to balance loads, by simultaneously introducing even more PCIe flexibility.