Asus Sabertooth 990FX
Asus attempts to extract maximum utility from AMD’s 990FX and SB950 chipset by providing ten USB 2.0 ports on the I/O panel and four PCIe x16 slots. Sabertooth 990FX buyers give up the secondary network and tertiary USB 3.0 controllers found on ASRock's board, but gain two additional internal SATA ports.
Performance seekers could be disappointed that both third-party SATA controllers operate at 3 Gb/s data rates, that two of the PCIe x16 slots share sixteen lanes, that the x16 slot in the middle is limited to four lanes, or that this is the only board in today’s round-up that lacks any Port 80 diagnostics display.
Asus, on the other hand, stresses both quality and stability as features. Unfortunately, we can’t test these boards for the years it would take to quantify the company's claims. However, Asus puts its money where its mouth is by backing the Sabertooth with a vastly superior five-year warranty. On the bright side, we get at least get some insight on firmware quality and system stability during our upcoming overclocking evaluation.
PCIe lane sharing is, in fact, one place where the Sabertooth beats ASRock's Fatal1ty. While the competition fixes its three slots as x16-x16-x4, the Sabertooth switches those same slots from x16-x16-x0 to x16-x8-x8 for added bandwidth to a third card. This should be fast enough for most three-way CrossFire and SLI configurations, though the board's bundle notably lacks the three-way SLI bridge you'd need.
Attached to only four PCIe 2.0 lanes, the center black slot is not intended for CrossFire or SLI. It can still host a fourth (single-slot) graphics card for added displays or PhysX calculations, even as the other slots are used in a three-way configuration. Some users might even want to place a high-performance drive controller there.
Asus proclaims quad-GPU SLI support, referencing a pair of dual-GPU GeForce GTX 590s. In fact, that arrangement is supported by all SLI-capable motherboards. Our problem with the quad-GPU terminology is that it almost appears to be an attempt to confuse neophytes into believing this four-slot board will take four cards working cooperatively. Asus clearly indicates on Page 2-16 of its manual that this is a triple-card SLI design, though.
An innovator in single-clip DIMM slots, Asus actually uses an AMD-specific version for the Sabertooth 990FX (compared to its competitor’s upside-down slots). And yet, while Asus' design is directionally correct, neither single-sided design is particularly useful in boards that have this much space between memory and the first graphics card.
The biggest layout concern we spot is still decidedly small: the latch atop the eight-pin CPU power connector faces up, and is blocked by the eight-lead cable whenever that cable is routed over the top of the board from behind the motherboard tray. Asus simply ran out of space to lay down this connector any other way.
Four SATA cables are enough for most builders. Though the Sabertooth 990FX does support up to eight internal drives, we’d probably use the two 3 Gb/s ports for front-panel eSATA. We are a little disappointed to see only one SLI bridge accompanying a board that should (in theory and according to its manual) support three-way SLI.
