A new reference motherboard design

As has become customary for Nvidia chipset launches, the nForce 790i SLI Ultra rolls out on a new reference motherboard that will be sold as-is by the likes of XFX, EVGA, and others. The board is a six-layer design, and at least in Ultra garb, it's expected to sell for $350 and up. Only those with deep pockets need apply.

Motherboards in this price range essentially need to be perfect, and the 790i reference design gets off to a good start. Dressed in blacks and greys with only a splash of green on its PCI Express x16 slots, the board looks appropriately menacing and definitely distinctive. More importantly, the layout puts everything in its right place, all but eliminating clearance issues and the potential for excessive cable clutter.

Around the socket, six power phases feed the CPU. Nvidia also says it has optimized traces to the processor to ensure that the actual data paths (and not just physical board traces) are all exactly the same length.

Not that you're going to notice little traces when there's a virtual mountain range of chipset and voltage regulation circuitry cooling ringing the socket. This generous array of nickel-plated heatsinks is the most expansive we've seen coupled with an nForce chipset. Despite cutting an imposing profile, it does a remarkably good job of staying out of the way. We were even able to squeeze a massive Ninja CPU heatsink onto the socket without interfering with the chipset cooler.

When running at stock speeds, the chipset heatsinks can easily get by with silent, passive cooling, even on an open test bench with little ambient airflow. Nvidia also includes a snap-on cooling fan that's recommended for overclocking. The fan plugs right into the motherboard, and although you can adjust its speed through the BIOS, it doesn't benefit from temperature-based automatic fan speed control.

nForce chipsets have a reputation for running a little hot, so it's encouraging that the auxiliary fan is only necessary for more extreme overclocking. The metal bracket that holds the fan in place could use a little work, though; it snapped off when we installed the fan, and although that doesn't compromise the integrity of the chipset cooler, no one wants little bits of their motherboard falling off.

Below the chipset cooler's fan mount lies a vapor chamber that extends down to the south bridge. Designed for efficient heat transfer from a notoriously toasty MCP chip, this link is lined with low-profile cooling fins that provide plenty of clearance for longer graphics cards. You don't have to worry about gargantuan expansion cards interfering with onboard ATA or Serial ATA ports, either—they're all located along the edge of the board or otherwise tucked out of the way.

Nestled between the board's edge-mounted storage ports we find a two-digit POST code display that takes the beep-code guesswork out of troubleshooting boot problems. Nvidia also throws in handy onboard reset and power buttons for those who build or test systems outside standard enclosures.

Those onboard buttons sit at the bottom of a generous slot stack that boasts three PCI Express x16 slots. The first and third slots have PCIe 2.0 lanes, while the second is a gen-one slot connected to the south bridge. This arrangement nicely spaces two-way SLI configurations, providing plenty of breathing room even with double-wide cards. Those double-wide SLI configurations will also leave users with free PCI and PCIe x1 slots in addition to the third x16 slot.

Atop the slot stack, you can just make out a red Serial ATA port. This is the board's seventh internal SATA port, and it's connected to an auxiliary JMicron JMB362 SATA controller. Nvidia amusingly suggests the placement of this port is ideal for optical drives, which seems odd, because the board has four other internal SATA ports that are much closer to where optical drives would be mounted in most enclosures.

A more likely rationale for the red port's placement is the fact that the JMB362 controller is also responsible for External Serial ATA connectivity on the port cluster. There, we find a single eSATA port—the first on an Nvidia motherboard design. With six internal SATA connectors already fed by the chipset, Nvidia might have been better off making both of the JMicron controller's SATA ports external.

eSATA connectivity nicely fills out a port cluster loaded with all the staples, including coaxial and TOS-Link flavors of digital S/PDIF audio output. Thanks to a Realtek ALC888S codec chip, it's possible to output multi-channel DTS Connect audio through those digital outs.

In addition to the external ports, onboard headers are available for an extra Firewire and four more USB ports. These headers are particularly important for the Enthusiast System Architecture specification, which relies on USB connections to talk to compliant components.