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X48 heavyweights go head to head

Asus and Intel at the high end
— 11:33 AM on April 28, 2008

Although Intel's processors and chipsets have long been embraced by PC enthusiasts, the company's motherboards have largely been ignored. Years ago, it was easy to see why. Intel motherboards didn't come with the tweaking and overclocking options that we crave, and that was understandable, since we never really expected Intel to endorse overclocking. However, times have changed, and so has Intel's tune. The firm now has several products targeted specifically at enthusiasts, including the new DX48BT2 "Bonetrail 2" motherboard that comes loaded with many of the features we'd expect from a modern, high-end mobo.

Based on Intel's flagship X48 Express chipset, Bonetrail's second coming faces stiff competition from Taiwanese mobo makers with far more street cred in the enthusiast space—credibility that, for the likes of Asus, is well deserved. Asus one of the biggest players in the motherboard market, and it's been catering to enthusiasts for as long as I can remember. Asus has embraced the X48 Express, as well, most recently with its Rampage Formula motherboard.

The Rampage Formula and DX48BT2 effectively target the same market, albeit with one DDR2 memory and the other with DDR3. For once, however, Intel is the underdog. Read on to see if the processor giant can beat Asus at its own game.

Manufacturer Intel
Model DX48BT2
Price (Street)
Availability Now

Intel's DX48BT2 motherboard
Designed for enthusiasts, seriously

Intel introduced its first Bonetrail board, the DX38BT, last year with its then-flagship X38 Express chipset. The X38 has since been replaced by the X48 Express to accommodate the Core 2 Extreme QX9770's 1600MHz front-side bus, bringing with it a Bonetrail redux in the DX48BT2. We really wish Intel had stuck with the Bonetrail code-name here; DX48BT2 doesn't exactly roll off your tongue, although we can at least take some solace in the fact that the board avoids banal Extreme Edition branding. If you look closely, though, the BT2's Bonetrail roots shine through in the form of a couple of stylized skull logos emblazoned on the board.

As if the skull logo weren't tough enough, the DX48BT2 comes dressed in black and blue, like a tattooed biker in denim and leather.

In theory, Intel has an advantage over competing motherboard makers because it engineered the X48 Express chipset that lies at the DX48BT2's core. Given intimate knowledge of the chipset and its associated quirks, Intel's motherboard designers should be able to exploit the X48's potential fully. There's more to a good motherboard than pushing the chipset to its limits, though, starting with how all of the various slots, components, and connectors are laid out on the board.

The DX48BT2's layout begins well enough, with power connectors located along the edges of the board where their associated cabling won't interfere with airflow around the CPU socket. Intel also does well to place the board's single IDE port—powered by an auxiliary Marvell storage controller due to the ICH9R's lack of legacy ATA support—near the top edge where it will be close to the 5.25" drives bays of most enclosures.

Not that Intel's stock processor coolers need it, but there's also plenty of room around the CPU socket for larger heatsinks. The BT2 can easily accommodate Scythe's massive Ninja heatsink, and since there's so much room around the socket, installation is a snap. That's more than can be said for some enthusiast boards, which, if they do provide clearance for larger heatsinks, often leave little room to access the retention tabs that hold coolers in place.

Always the, ahem, rebellious non-conformist, Intel bucks the recent trend toward intricate networks of heatpipe-linked chipset and voltage circuitry coolers in favor of simple passive heatsinks. The modest array of heatsinks makes the Bonetrail board look a little sedate next to its competition, but if anyone knows how much cooling the X48 Express north bridge requires, it should be Intel.

The DX48BT2's ICH9R south bridge chip gets away with a low-profile passive heatsink that leaves plenty of room for longer graphics cards. Unfortunately, though, double-wide graphics cards have the potential to block access to the board's Serial ATA ports. The ports are smartly placed out of the way along the edge of the board, and they're arranged in pairs presumably to provide additional clearance. However, the spacing isn't quite right, which is problematic if you plan on running a double-wide card longer than nine inches.

If you're willing to sacrifice SATA ports, you can actually run up to three double-wide graphics cards in the DX48BT2. Thanks to its X48 Express north bridge, the board has 32 lanes of PCI Express 2.0 connectivity split evenly between its top two PCIe slots (blue in the picture above). The third physical PCIe x16 slot gets four lanes of gen-one PCIe connectivity via the ICH9R south bridge chip. This slot could prove useful if you're looking to run a three-way CrossFire configuration.

Despite the three PCIe x16 slots, the BT2 is actually a little short on expansion capacity. A couple of PCI slots are provided, but that only brings the slot count up to five—two fewer than other X48-based designs. Fortunately, the backward compatibility provisions built into the PCI Express spec will allow the board's x16 slots to work with PCIe x8, x4, and x1 cards.

Intel populates the DX48BT2's port cluster with a decent array of connectivity options, including a couple of External Serial ATA ports powered by the same Marvell controller responsible for the board's IDE port. A TOS-Link digital S/PDIF audio output is also provided, alongside a full complement of analog audio ports backed by an eight-channel Sigmatel 9274D HD audio codec. We don't see Sigmatel codec chips used much, but the BT2's implementation was apparently good enough to earn the board a Dolby Home Theater certification.

Eight USB ports fill out the cluster, which is conspicuously devoid of PS/2, serial, and parallel connectivity. We can live without the legacy ports—it's 2008, folks, time to move on—but Intel would have been wise to offer a little something extra in their place. The DX48BT2 could do with a couple of additional USB ports (onboard headers are available for four more ports), a coaxial S/PDIF output, and a digital S/PDIF input port.