The ASUS Maximus III Extreme is a bit of a cluttered board. This is not too surprising as it is packing a total of five PCIe x16 (mechanical only; two are fully x16 electrical) slots on it in addition to quite a bit of heat pipe just to keep things cool.
If you had any doubts that ASUS is trying to beef up the Maximus III Extreme, then you really only need to look as far as the upper half of the board. It is littered with high quality solid capacitors and solid ferrite chokes. These should, in combination with the ASUS custom digital VRM (called Extreme Engine Digi+), help to keep the power flowing consistently to your CPU, memory and peripherals.
The upper half of the Maximus III Extreme looks like a normal ATX form factor board at first glance. But only at first glance; if you look any longer than half a second you will see some very intriguing features. One of the first that caught my eye was the ProbeIT monitoring pads. Here you can connect a multi-meter to read the voltages that are actually rung through the board. This does not rely on the BIOS to push out numbers and allowed us to note that our Maximus III Extreme was running about .025-.03 volts lower on the CPU VID than was set in the BIOS. This helped us fix more than one overclocking problem we had. The next is the "Go Button". This button allows you to quickly and automatically set your memory to speeds that will allow a clean post. Although the button is named something different, it is the same as the MemOK! button on other ASUS boards.
The LGA 1156 CPU socket area is clean, but seems a little tight. Fortunately it only seems tight. For the most part the layout is done well enough that you can fit a pretty oversized cooling setup here without having any problems.
ASUS is also using a single large 3V 1000 microfarad FPCAP (Functional Polymer Capacitor). This should seriously help to maintain clean and stable power, especially under heavy overclocking when stable power is very important.
Of course the 8-pin E-ATX power connector is still in a cumbersome spot, but that is not that surprising as it is a limitation of the ATX form factor. However, the placement of the CPU fan header is not; for some reason ASUS put this is an very awkward place which makes it more than a little tricky to get into place. One thing that we do want to point out here is the barely visible flat red button. This is not labelled on the board but is intended for LN2 users. It allows a disconnect from power to attempt to allow a CPU to recover from any sub-zero post issues it might have. This button is used in conjunction with the LN2 jumper located right behind the Go Button.
Speaking of power, ASUS has included two extra 4-pin Molex connectors to ensure that you are giving the Maximus the right level of power to maintain the higher clocks. One is located right in front of the Audio I/O riser and the other at the bottom edge of the board. The upper one is not well positioned and can make cable management a tad rough depending on the location of your PSU.
Moving down to the lower half of the board, we find the five x16 slots we talked about earlier in the article. They are setup to allow up to four GPUs to run in conjunction (four for quadfire). However, on the first two they will give you full x16 performance. This is slot 1 and 2. If you drop in a third GPU you will get dual x16 plus x8 and with four GPUs you get four x8 slots. According to the manual you should not use slot 3 for a GPU, but stick with slots 1,2,4 and 5.
One item to take note of in this area is how close the top slot is to the NF200 heatsink. As ASUS is using a PCIe bridge chip to ensure enough PCIe 2.0 lanes for dual x16 SLI and Crossfire performance, they do have to cool this power hungry monster. But unfortunately it puts it between the CPU and your GPU. This NF200 generates some pretty good heat and even at idle the heatsink sits at around 32c. When you push the GPU it can pop up to around 36-37c and creates a small pool of heated air that can be a pain to deal with.
The other side of the board houses the P55 MCP as well as the Marvell SATA 3.0 controller and PCX bridge chip for those extra PCIe Gen 2.0 lanes (this time for proper SATA 3.0 and USB 3.0 support). Both the P55 and the Marvell controller are covered by a nice large heatsink that is connected to the NF200 and VRM cooling via a heat pipe. In the bottom right hand corner of the board you will see another of those flat red buttons; this one is a BIOS reset button.
Taking a look at the back I/O plane, we see a divergence from what you are used to on a less enthusiast based board. Here we have the typical connectivity ports, but we also find another CMOS reset button, the iROG connect button and USB port, and a 10-pin header for the Bluetooth module.
Although the Maximus III Extreme is cluttered and chaotic looking, when you stop and think about what is packed into this board, ASUS has done a pretty good job of organizing the layout. I do want to mention one thing that I did not cover above; the Maximus III Extreme is simply loaded down with LEDs. They are literally all over the board. I will not go into detail here, but ASUS has given you visual indicators of voltage for the CPU, PCH, DDR as well as simple lights to show that other items are operational. They are all covered in the manual, so I will not detail everything here.