When we first heard about the 1156 socket CPU motherboards (P55), these newer motherboards were supposed to carry a newer SATA controller. This new SATA controller was supposed to handle the new and faster SATA III (or SATA 6gb/s) HDDs. Unfortunately something was wrong with the initial SATA III controller, which inevitably delayed the arrival of SATA III capabilities. After a few months passed, and the SATA III controller issue was resolved, motherboard manufacturers can now bring us SATA III capabilities.
GIGABYTE is one of the first motherboard manufacturers to adopt this newer type SATA III HDD interfacing. One of these motherboards to get this new standard is GIGABYTE's P55A-UD4P. This motherboard is not much different from the original P55-UD4P, review can be found HERE, except this one carries a SATA III controller, and uses an a designation in the name to differentiate between these two motherboards. (actually GIGABYTE will be adding an a designation to all of their motherboards containing the newer SATA III interface, all Giga boards with the P55A will have Sata 3 and USB 3.0)