Board layout is something of a pet peeve with me. I have become very disappointed with the way most motherboard makers are laying out current ATX boards. The problem arises from the placement of slots and components. In some cases component placement cannot be altered as the traces (thin lines of conductive material that run under the laminate and layers of the board) have to be laid out in a certain way to prevent signal bleed or cross-talk. However, there are other items that can and often should be moved or simply left off of today's motherboards.
The ASRock P55 is not much different, there are items that are placed in awkward or hard to reach spots as well as slots and items that really have no place on the board.
Starting at the top of the board we see the typical ATX style layout. The CPU is slightly left of center with the four DDR3 slots to the right. The 24-pin ATX power socket is also here on the right edge of the board. As we have mentioned this placement is nice whether you have a bottom or top mounted PSU. It allows you (in most cases) to run the main power cable behind the backplane in the case and out of the way. However, this handy placement is marred by the awkward placement of the ASRock "Smart Switch Design" power and reset switches. Having them this high on the board is okay when on the test bench, but almost useless when mounted in a case. Of course, you could argue that in the case you can use the front panel switches easily enough.
The 8-pin auxiliary power header is located at the top left of the board. This is one of those cases where we see something in an awkward place. If you try to plug this in when the board is mounted, it is very difficult to reach. The heatsinks covering the power regulators are in the way and you end up with bloody knuckles. ASRock also put the CPU fan header in a rather odd place. It is right above the primary PCI-e x16 slot.
ASRock has implemented a total of 16 CPU power phases with three gear switching with its IES or Intelligent Energy Saver design. The gearing allows for switching between different amounts of power phases depending on system load. Looking closely at the CPU socket we see the new LGA-1156 hold-down clamp and something interesting. Notice that there are two holes in the board where you would mount the CPU fan. This feature that ASRock calls "Combo Cooler Option" or "CCO" allows you to use any existing Socket 775 cooler on this board for your Socket 1156 CPU. This is a great feature as many people who would be interested in the P55 Deluxe would already have a high-end CPU cooler.
Moving down the board we again see things we expect in an ATX form factor. The big difference here is that there is no Northbridge in the middle of the board. It is just not there. This is because it no longer needs to be. The Intel P55 Express chipset can be safely (and effectively) moved to where the Southbridge used to sit. This can help to economize the available space on a motherboard.
ASRock is still using the 90 degree angled SATA and PATA connectors as well as the clipless PCI-e slots. These are both great features and ones that, although small, make a big difference when assembling a system.
It is in the slot area that I have the most problems with modern board design. If you look at the image above, you can see what I am talking about. The first legacy PCI slot is so close to the primary PCI-e adapter that any mid-range to high-end card will make it useless. This slot should just not be there. Next is a PCI-e x1 slot, in all honesty this should be moved above the primary PCI-e slot or at the bottom of the board. This same problem is seen in the additional two legacy PCI slots. Some serious thought needs to go into this area of the board for future products especially in the high-end/enthusiast boards.
Along the bottom of the board ASRock has put in the usual large number of headers, from the front panel header to the large number of USB headers. ASRock has also thrown in the now familiar diagnostic LED that it calls Dr. Debug.
For I/O the ASRock has the usual suspects as well as an additional 1GB Ethernet connection. There is also a clear CMOS button. This makes resetting the BIOS fairly easy if you have issues that cause the system to stop responding as a result of overclocking.