Asus P7P55D-E PRO, found here... http://za.asus.com/Motherboards/Intel_Socket_1156/P7P55DE_PRO/
theres your problem.. the SATA 3 uses the Marvell 912x controller. This controller has known issues with SATA 3.. your SATA 2 ports would probably end up better. Same issue with the i7 1366 boards that use this controller.
google that controller and ssd and you will see
