Board Layout

Crosshair III Formula on left, M4A79T Deluxe right

For an ROG motherboard, the Crosshair III Formula looks pretty sparse when it isn’t populated with system components like the CPU and its cooling, RAM, GPU, and SATA cables. It looks far less busy than the M4A79T Deluxe with its six expansion slots (4 PEG slots and two PCIs), and in comparison to other ROG motherboards ASUS has released over the last few years, the Crosshair III Formula looks downright spartan.

As a result, there aren’t a lot of areas for potential layout conflicts on the board. There’s tons of space everywhere it seems.

Everywhere it seems but the area between the AM3 socket and the DIMM slots. Unfortunately there isn’t enough room for our Zalman CNPS 9700 heatsink/fan unit and our Corsair Dominator or OCZ Reaper HPC memory modules. Memory modules like these have very tall heatspreaders that bump up against the bottom of our Zalman heatsink.


In order to get both components to fit, you have to bend the first memory module ever so slightly; the memory module functions fine on the board in this orientation, but over time this could potentially damage that first DIMM slot and the memory module itself. The only solution to this problem is to pick up memory modules with shorter, more conventional heatspreaders like the OCZ Platinum line or move the memory modules to the third and fourth DIMM slots.

Keep in mind however that this isn’t ASUS’ fault. This is a problem that’s present on all AM3 motherboards, not just the Crosshair III Formula. Blame AMD for not defining enough keep away space between the CPU socket and the DIMM slots in the AM3 socket spec.

That’s the only real issue with the Crosshair III Formula. ASUS nails it everywhere else with the board’s design. You’ve got five total SATA ports, with four of the five ports oriented parallel to the edge of the PCB, so they don’t interfere with long dual slot graphics cards like the GeForce GTX 295 and Radeon 4870 X2. The fifth SATA port is mounted just above the four-port SATA cluster, but it’s placed where it wont interfere with anything.


You may wonder why the motherboard ships with just five internal SATA ports. This is because the AMD SB750 South Bridge only supports up to six SATA drives. ASUS uses the sixth SATA port to provide eSATA functionality on the back panel of the Crosshair III Formula.


Another item we should note are the two x1 PCIe slots. Technically the board sports three PCIe slots, but the uppermost (black) slot is required in order for the SupremeFX X-Fi audio module to operate. If you try plugging the audio module into one of the white PCIe slots, it won’t work. ASUS says they’ve designed the black slot specifically to work with SupremeFX.

Considering the amount of empty space on the PCB, it’s a bit surprising that ASUS didn’t just integrate the SupremeFX module on the PCB like they did for the Rampage II Gene. That way you wouldn’t have to give up a PCIe slot.

One nice adjustment ASUS has integrated on the Crosshair III Formula versus the M4A79T Deluxe is the fan headers. Not only does the Crosshair III Formula sport more fan headers – 6 versus 3 – they’re also more powerful 4-pin headers. This allows you to mount beefier coolers directly to the board if you want.


Like other ROG motherboards, ASUS also mounts three temp headers to the Crosshair III Formula in case you’d like to hook a temp probe to the board and watch component temperatures. When paired with their corresponding fan headers, the two can work in concert with each other to keep your system components as cool as possible.

Crosshair III Formula on left, M4A79T Deluxe right

ROG logo in center of heatsink

The cooling ASUS has integrated on the Crosshair III Formula is slightly more powerful than the cooler used on the M4A79T Deluxe. The MOSFET cooler is larger, with considerably more fins. The same applies to the South Bridge heatsink as well. ASUS says that their pin-fin thermal module used on the North Bridge performs better than the traditional stacked-fin cooler, with greater surface area and better airflow. Honestly though the 790FX chipset isn’t a large heat generater, so all the fancy heatsinks and heatpipes are more than enough to keep everything cool, even under load during OC’ing. Also, as we mentioned on the previous page, the Crosshair III Formula sports an 8+2 phase power design, just like the M4A79T Deluxe.