The P7P55D-E Pro follows the very familiar ATX form factor. The top of the board is dedicated to the CPU and memory while the lower half is all about the peripherals.
Of course there is more to it than that, but in general terms it is much like every other motherboard on the market.
Taking a quick look at the layout, we do see some nice touches that ASUS has thrown in. For starters, they have included a pair of SATA II ports up near the 24-Pin ATX Power socket. These are well placed for SATA DVD/CD/Blu-ray drives. ASUS has also continued with their one-armed RAM slots. We have come to like these very much and have found that they do not have any issues keeping your RAM firmly in place.
The area around the CPU socket is well organized, but has a small problem. If you look at the upper left mounting hole you will notice that the area is very constricted. This can cause issues with certain heatsinks like the Thermalright Venomous X for the 1156 socket. The heatsinks for the PWMs also get in the way here and make installation and removal a little of a pain. On the positive side, ASUS has continued the inclusion of two 4-pin fan headers here for use with a push/pull air cooling system.
Another annoyance with the current layout is the unfortunate placement of the 8-pin Aux power socket. However, this is not a failing on the part of ASUS. The ATX layout and the increasing demand for power by most modern systems forces the inclusion of this and the need to have it close to the source puts it in an awkward spot.
As ASUS is a company that puts the enthusiast first, they have included a couple of features in this upper area to help the enthusiast get the most out of their P7P55D-E Pro. The first and least exciting is a 3-pin fan header; this allows easy installation of a RAM cooler. Right next to this is a small switch; this is the DRAM Overvolt switch. Moving this to the right (as seen in the image) enables advanced voltage options for RAM in the BIOS. The last is the MemOK button; this allows you to quickly tune any RAM automatically for a clean boot.
Moving towards the bottom of the board we see that ASUS has put some distance between your GPU and the CPU. They did this by dropping in a single x1 PCIe 2.0 slot. The rest of the slots are a nice compromise and allow for good flexibility for different user needs.
Moving to the right hand side of the P7P55D-E Pro, we see the rest of the SATA II ports, a single e-SATA port (to go with the bracket) and the two SATA 3.0 ports (the white ones). The controller for these is the Marvell SE9123. This is connected to a PLX bridge (along with the NEC USB 3.0 controller and the two PCIe 2.0 x1 slots) before connecting back into the system along a single PCIe gen one lane. The Marvell controller is underneath the star shaped (well, sort of star shaped) heatsink.
The I/O ports area is pretty typical, with the obvious exception of the two USB 3.0 ports. These are the blue colored ports under the single LAN port.
The P7P55D-E Pro is a nicely laid out board despite some of the limitations of the ATX form factor. It offers excellent flexibility in the peripherals that you can drop in. We have to say that it is one of the better thought out boards and in practice (with a few minor exceptions) is also one of the easier to use.