ASUS Crosshair IV Formula Motherboard
By Gabriel Torres on April 30, 2010


The AMD 890FX is the new high-end chipset for AMD processors and the ASUS Crosshair IV Formula is one of the most high-end motherboards based on this new chipset, bringing all features high-end users could dream off: four PCI Express x16 slots, six SATA-600 ports, two USB 3.0 ports, gold-plated audio connectors, Japanese solid capacitors, extensive overclocking support and more. Check it out.

This new high-end chipset is a two-chip solution. The main feature of the north bridge chip is the presence of 42 PCI Express x1 lanes – almost double the amount present on AMD 890GX chipset (22 lanes) – which allows a very high-end configuration for the expansion slots as we will explain in the next page. The south bridge chip used is an SB850, the same one used on the AMD 890GX chipset. The main feature of this chip is the native support for six SATA-600 (a.k.a. “SATA 6G”) ports, so the motherboard doesn’t need an external chip to support this feature, and certainly the AMD 890FX and 890GX will help the new SATA standard to become mainstream.

In Figure 1 you can have an overall look from ASUS Crosshair IV Formula.

ASUS Crosshair Formula IV motherboard
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Figure 1: ASUS Crosshair IV Formula motherboard.


As mentioned, the AMD 890FX chipset has 42 PCI Express x1 lanes – just to put things into perspective, the AMD 890GX chipset has 22 lanes. This allows this chip to provide a very high-end slot configuration. On Crosshair IV Formula ASUS decided to hook up these lanes like this: the first PCI Express x16 slot always work at x16, independently of how many video cards are installed; the second PCI Express x16 slot always work at x8; the third PCI Express x16 slot works at x16 when two video cards are installed or at x8 when three video cards are installed; and the fourth slot always work at x4.

So it is really important to use the first and the third (and not the second) PCI Express x16 slots when using two video cards in order to get the best performance possible.

It is important to note that motherboards from other manufacturers may use a different configuration. With 42 available lanes it is possible, for instance, to have four PCI Express x16 slots working at x8 at the same time.

The motherboard also comes with two standard PCI slots.

It is important to note that in order to fit so many slots on a motherboard without making it to be bigger than ATX form factor, there is no space between the third and fourth PCI Express x16 slots, as you can see in Figure 2. This means that if you install a dual-slot video card on the third PCI Express x16 slot you automatically “kill” the fourth PCI Express x16 slot. And you will need a case with eight slots for installing a dual-slot video card on the fourth PCI Express x16 slots (plus the video card will block access to the buttons and headers located near this slot, see Figure 2). These issues should not be a problem for most users, but if you are willing to build the ultimate gaming machine with four video cards under CrossFireX mode, you should keep them into consideration.

ASUS Crosshair Formula IV motherboard
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Figure 2: Slots.

Near the fourth PCI Express x16 slot the motherboard has a series of buttons: overclocking (“O.C.”), which allows the motherboard to automatically overclock itself for you; core unlock, which unlocks “hidden” CPU cores available on certain Phenom CPUs; power; and reset.

Memory Support

AMD CPUs have an embedded memory controller, meaning that it is the processor, and not the chipset, that defines the memory technologies and the maximum amount of memory you can have. The motherboard, however, may have a limitation as to how much memory can be installed.

At the moment, the integrated memory controller of socket AM3 processors supports only DDR3 memories up to 1,333 MHz under dual-channel architecture, however ASUS says Crosshair IV Formula supports DDR3 memories up to 2,000 MHz through overclocking. This motherboard has four DDR3 sockets and since, at the moment, each DDR3 memory module can have up to 4 GB, you can have up to 16 GB with it.

The first and the third sockets are black, while the second and the fourth are red. In order to achieve the maximum performance, you should install two or four memory modules to enable the dual-channel architecture. When only two modules are used, install them in sockets with the same color in order to enable this feature.

ASUS Crosshair Formula IV motherboard
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Figure 3: Memory modules. Install two or four modules for the best performance.

Like other high-end motherboards from ASUS, Crosshair IV Formula features the “MemOK” button, that tests the memory modules to see if they are compatible with your system (the results from this test are shown on your video monitor).

ASUS Crosshair Formula IV motherboard
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Figure 4: MemOK! button.

This button can be used also to load an overclocking profile after the operating system is loaded.

On-Board Peripherals

As explained earlier, the AMD 890FX chipset is a dual-chip solution using the SB850 south bridge chip. This chip natively supports six SATA-600 ports (with RAID 0, 1, 5 and 10) and obviously ASUS Crosshair IV Formula comes with all of them, placed on the motherboard edge rotated 90°, so video cards won’t block them, as you can see in Figure 5.

ASUS Crosshair Formula IV motherboard
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Figure 5: SATA-600 ports.

A JMicron JMB363 chip provides two additional SATA-300 ports, one near the SATA-600 ports (see Figure 5 this port in black) and one as an eSATA-300 port on the motherboard rear panel.

No parallel ATA (PATA, a.k.a. IDE) port and no floppy disk drive controller are present.

This motherboard has 12 USB 2.0 ports, seven soldered on the rear panel and five through three headers located on the motherboard. Since there is an odd number of ports on the motherboard, one header (the one labeled “USB7”) only supports one port, so pay attention to not install the cable coming from the front panel from your case on this port, otherwise one of the USB ports from your case won’t work.

This product also has two USB 3.0 ports on its rear panel (the blue ones), controlled by a NEC μPD720200 chip.

Two FireWire (IEEE1394) ports are provided, one standard-sized on the rear panel and one through a header on the motherboard. They are controlled by a VIA VT6315N.

The motherboard comes with an I/O bracket containing two USB ports and one FireWire port.

Eight-channel audio is generated by the chipset using a VIA VT2020 codec. Unfortunately this component isn’t listed on VIA’s website; the only information we could find out is that it presents a 110 dB signal-to-noise ratio on its outputs, which is a professional-grade number. Crosshair IV Formula comes with an on-board optical SPDIF output and you can add a coaxial SPDIF output installing an adapter on the motherboard “SPDIF_OUT” header.

The analog audio connectors are independent and gold-plated.

ASUS Crosshair IV Formula has one Gigabit Ethernet port, controlled by a Marvell 88E8059 chip, which is connected to the system using a PCI Express x1 lane and thus not presenting any potential performance issues. This particular controller incorporates features to off-load some tasks from the system CPU and thus improve networking practical performance (for example, TCP/IP and UDP checksum calculation and check and TCP segmentation, and support for IEEE 802.1QAV standard for audio video bridging, AVB, for better quality of service on real-time audio and video transmissions).

On-Board Peripherals (Cont’d)

In Figure 6, you can see the motherboard rear panel with keyboard PS/2 connector, seven USB 2.0 ports (black ones), clear CMOS button, two USB 3.0 ports (blue ones), optical SPDIF output, FireWire port, eSATA-300 port (green one), one Gigabit Ethernet port, ROG Connect button and independent analog 7.1 audio outputs.

ASUS Crosshair Formula IV motherboard
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Figure 6: Motherboard rear panel.

No mouse PS/2 connector is available, thus you have to use a USB mouse with this motherboard.

The ROG Connect feature is quite interesting. It allows you to use the seventh USB 2.0 port from the rear panel (the one near the ROG Connect button) to connect your PC to another computer (a laptop, for example) through a cable that comes with the motherboard for overclocking and diagnosing your computer from the second computer.

Speaking of diagnosing, instead of a POST display Crosshair IV Formula has a series of four LEDs that indicate which component is failing when the computer is not turning on (see Figure 7).

ASUS Crosshair Formula IV motherboard
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Figure 7: Diagnostics LEDs.

There are several other smaller features targeted to enthusiasts. For example, all the connectors for auxiliary fans support PWM technology in order to automatically control the speed of each fan, and on three of them the motherboard supports the installation of a thermal sensor in order to control the fan speed according to the temperature on where you installed the corresponding thermal sensor.

In Figure 8, you can see all accessories that come with this motherboard.

ASUS Crosshair Formula IV motherboard
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Figure 8: Accessories.

Voltage Regulator

ASUS Crosshair IV Formula comes with a ten-phase voltage regulator circuit. From the ten available phases, eight are used to generate the CPU main voltage (Vcore) while the other two are used to generate the voltage required by the integrated memory controller. Thus this motherboard has a “8+2” configuration.

This motherboard comes with a passive heatsink installed on top of the transistors from the voltage regulator circuit, connected to the passive heatsink that is installed on top of the north bridge chip using a heatpipe, which is also connected to the heatsink from the south bridge chip. In Figure 9, you can see the voltage regulator circuit with this cooling solution installed and, in Figure 10, with it removed.

ASUS Crosshair Formula IV motherboard
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Figure 9: Voltage regulator circuit.

ASUS Crosshair Formula IV motherboard
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Figure 10: Voltage regulator circuit.

As mentioned earlier, all capacitors used on this motherboard are solid made in Japan and the voltage regulator circuit uses ferrite chokes, which are better than iron chokes. Please read our Everything You Need to Know About the Motherboard Voltage Regulator tutorial for more information.

Overclocking Options

Keeping the ASUS tradition on the high-end market, Crosshair IV Formula comes with a myriad of overclocking features. First let’s talk about the hardware-based overclocking features present on this product.

As already shown in Figure 2, this board has an automatic overclocking button and, as shown in the previous page, a USB connection called ROG Connect to allow you to overclock and diagnose your system from another computer.

Crosshair IV formula has four LEDs to indicate at which range the voltages from the CPU, north bridge, south bridge and memory are at the moment. They can be in three different colors: green (normal), yellow (high) or red (crazy). On page 2-2 from the manual there are several tables showing the voltage ranges that triggers each color. On the motherboard setup you can configure which voltage each LED will be displaying. For example, you can change the CPU voltage LED to display either the CPU voltage (VDD), the memory controller voltage (VDDNB) or the CPU embedded clock generator (VDDA).

The motherboard has points for you to manually monitor voltages using a multimeter, as you can see in Figure 11. You should put the black probe on the GND pad and the red probe on the pad corresponding to the voltage you want to monitor: VDDNB1 is the voltage from the CPU embedded memory controller, SB is the voltage from the south bridge chip, HT is the voltage from the HyperTransport bus, NB is the voltage from the north bridge chip, DRAM1 is the voltage from the memory modules, CPU_PLL is the voltage from the CPU embedded clock generator (a.k.a. VDDA) and CPU1 is the voltage from the CPU (a.k.a. VDD).

ASUS Crosshair Formula IV motherboard
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Figure 11: Point for monitoring voltages.

Let’s see now the overclocking options present on the motherboard setup.

Overclocking Options (Cont’d)

ASUS Crosshair IV Formula provides a myriad of overclocking options. Below we list only the main ones available on 0505 BIOS.

Memory timings can also be tweaked.

ASUS Crosshair Formula IV motherboard
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Figure 12: Overclocking menu.

ASUS Crosshair Formula IV motherboard
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Figure 13: Overclocking menu (Cont’d).

ASUS Crosshair Formula IV motherboard
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Figure 14: Memory timing options.

ASUS Crosshair Formula IV motherboard
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Figure 15: More options.

Main Specifications

ASUS Crosshair IV Formula motherboard main features are:

* Researched at on the day we published this First Look article.


ASUS Crosshair IV Formula is clearly targeted to the extreme enthusiast that is looking for a motherboard with the latest technologies such as SATA-600 and USB 3.0 ports for his or her AMD CPU but wants more than mainstream motherboards can provide. For example, this board can control up to five PWM fans according to the temperature measured by up to three different probes (sold separately). With its four PCI Express x16 slots and impressive number of overclocking features, this board will definitely please the user that is building the ultimate gaming machine based on an AMD CPU.

Of course this board is more expensive than mainstream products, however when we put into perspective that in the past we saw more expensive high-end motherboards for AMD CPUs providing less features, we think ASUS Crosshair IV Formula presents an exceptional cost/benefit ratio for the users it is targeted to.

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