Not All USB 3.0 Implementations Are Created Equal

Asus Crosshair IV Formula (NEC PD720200)

Asus’s Crosshair IV Formula is the firm’s top-of-the-line motherboard for AMD’s Socket AM3 processors, including everything from the Athlon II X2 up to the Phenom II X6. The board is based on the latest 890FX/SB850 AMD chipset and, like all other products in this review, uses the NEC controller and its two attendant USB 3.0 ports. The board still offers USB 2.0 connectivity via the chipset's USB 2.0 controller, so check for blue ports if you want to be sure you’re using USB 3.0.

We found that this motherboard delivers a fast USB 3.0 implementation, reaching 150 MB/s. However, it can register even higher performance if you install an add-on card. When doing this, we measured 172 MB/s with WD’s controller and 173 MB/s with Gigabyte’s add-on card. All other solutions, whether integrated or discrete, are all limited to between 113 and 168 MB/s. This is quite a difference. While we don’t have any insight on the specific implementation, it's obvious that there are disadvantages to this integrated solution. The add-on cards seem to take better advantage of PCIe connectivity, as all lanes on the 890FX chipset are fully PCI Express 2.0-compliant.