890FX Chipset and the ASUS Crosshair IV Formula

While the new Thuban CPUs will run fine in existing socket AM3 790FX motherboards with a BIOS update supporting the new processors, today AMD is also rolling out a new chipset, 890FX.

Again, like the 890GX launch a month ago, the new 890FX chipset isn’t a next-generation built from the ground up. It’s an evolutionary rather than revolutionary upgrade over its direct predecessor, with the most significant changes found in the South Bridge of the chipset.

Tweaks have been made to the North Bridge, but many of the key specs remain largely unchanged. PCI Express lanes for instance remains the same at 42, which is enough for 2x16 or 4x8 CrossFire (in comparison 890GX is limited to 2x8).

Like the 890GX chipset, 6x1 PCI Express 2.0 lanes hang off the North Bridge, which can be used by motherboard manufacturers to implement full bandwidth USB 3.0 support. While this isn’t as elegant as a native USB 3.0 interface that’s built-in to the chipset, it’s better than nothing.

890FX is paired with AMD’s SB850 South Bridge. As we mentioned in the 890GX article, it offers more USB support (14 USB 2.0 ports in SB850 versus SB750’s 12), a native Gigabit Ethernet MAC, and two additional x1 PCIe 2.0 lanes. Its most notable feature is its 6Gbps SATA support. SB850 supports up to six 6Gbps SATA drives.

The ASUS Crosshair IV Formula Motherboard

To test the capabilities of the new 890FX chipset, AMD sent us a Crosshair IV Formula motherboard from ASUS. The Crosshair IV Formula is ASUS’ newest Republic of Gamers motherboards, and is loaded with features that enthusiasts will appreciate.

The most notable is probably Core Unlocker. Unlike previous tools that relied on AMD’s ACC tool to unlock CPU cores, Core Unlocker uses the iROG processor that’s built-in to the motherboard to unlock processing cores that have been deactivated at the factory by AMD. ASUS also says that Core Unlocker can be used to enable L3 cache that’s been disabled by AMD in some Athlon II CPUs.

Crosshair IV Formula also ships with ASUS Turbo Key II.

While we never had any problems with it, some people (and websites) complained that ASUS’ TurboV EVO was too complicated. TurboV EVO, in case you didn’t know, is the marketing term ASUS developed for their iROG processor used on P55 motherboards. The iROG chip could automatically OC your CPU, doing all the work for you. OC’ing could be accomplished via ASUS’ TurboV Software, or you could do it from within a setting inside BIOS.


ASUS has made things simpler for the Crosshair IV Formula. All you have to do is press the Turbo Key II button located at the bottom of the motherboard, turn on the board, and walk away. The Turbo Key button will then shine red, the motherboard will power on and find the optimal OC speeds for the CPU, and then boot Windows. In our case, it took the iROG processor about 10 seconds to determine that 3.596GHz (16x224.8) was the optimal speed for our particular Phenom II X6 1090T chip. (BTW, we managed to OC our CPU over 4GHz doing things the old-fashioned way.)

To quote the GEICO commercials, it’s literally so easy, a caveman can do it. All you need to do is physically press a button on the motherboard and you’re done. If you don’t know how to press a button, you probably have a very hard time turning on your PC each day and wouldn’t be reading this website.

To undo it, press the Turbo Key button again and it will go from red to white, letting you know that the CPU is no longer OC’ed.

Rebooting your PC won’t affect Turbo Key, the next time your PC boots up, it’s still OC’ed. Even from a cold boot. It’s simply the easiest way to safely and easily OC your processor that we’ve ever seen on a motherboard.

Other Republic of Gamers features like the Go Button, GameFirst networking, SupremeFX X-Fi audio, and ROG Connect carry over to the Crosshair IV. Two USB 3.0 ports are available on the board as well.