ASUS' P7P55D-Deluxe motherboard is a socket 1156 Core i5 platform representing the flagship feature set. Along with the obvious support of Intel Lynnfield socket 1156 processors, the ASUS P7P55D-Deluxe motherboard features three PCI Express 2.0 x16 videocard slots for multi-graphic card set ups. It's not triple x16 mode however, rather one VGA at x16 or two at x8/x8, and an additional PCI Express 2.0 x16 slot that's really just a PCI Express x4 in disguise (black above).
"Further expansion comes via a pair of PCI Express x1 and PCI slots. The P7P55D-Deluxe supports ATI Quad-GPU CrossfireX and nVidia Quad-GPU SLI, though you'd be hard pressed to find many users clamoring for a Geforce right now. There are four dual channel DDR3-1333/1066 memory slots which can accommodate up to 16GB of DDR3 RAM. Memory can be overclocked to run at DDR3-2133/1600 speeds with compatible modules."