Single page Print

Nvidia's nForce 680i LT SLI motherboard


Cutting costs with a new reference design
— 8:00 AM on March 26, 2007

NVIDIA LAUNCHED ITS NFORCE 680i SLI chipset late last year, and it arrived in style on a motherboard designed and made by Nvidia itself. New chipsets often debut on reference motherboard, but those boards are typically meant as validation vehicles for the chipset and as design guides for mobo makers; they don't have the polish one would expect from retail products. With the 680i SLI, however, Nvidia set out to build a reference design not only polished enough for retail, but robust enough to satiate overclockers and enthusiasts.

They succeeded, too. Nvidia's nForce 680i SLI reference design was rebadged and sold essentially as-is by the likes of Biostar, BFG, ECS, and EVGA. We were impressed by the board, particularly its ability to hit extremely high front-side bus speeds and to fully exploit the features and extras inherent to the nForce 680i SLI chipset.

The nForce 680i SLI's only lingering problem has been the cost of the platform—boards based on Nvidia's reference design typically run about $250, and custom boards from other partners can cost upwards of $300. Today, Nvidia is lowering the cost of entry into the 680i fraternity with the launch of the nForce 680i LT SLI chipset. Like its older brother, the LT arrives on an Nvidia-designed retail motherboard. This time, though, boards are expected to sell for $200 or less.

What has Nvidia cut from the 680i SLI to slide this latest LT design under the $200 mark? How does the board fare as a result? Is this Nvidia's homage to Lawrence Taylor? Read on to find out.


A new chipset? Really?
Before exploring Nvidia's latest foray into the motherboard world, I should take a moment to clarify exactly how this new LT version of the nForce 680i SLI differs from the original. Both chipsets support front-side bus speeds up to 1333MHz, but Nvidia characterizes the LT's overclocking prowess as simply "great," while the standard 680i SLI is apparently qualifies as "best." The standard 680i SLI also supports SLI-Ready Memory—Nvidia's entirely unnecessary rebranding of Enhanced Performance Profiles (EPP)—up to speeds of 1200MHz, but the LT's EPP support is limited to 800MHz. Beyond that speed, you'll have to actually tweak memory timings yourself. Perish the thought!

Unfortunately, no amount of BIOS fiddling will make up for the fact that the LT also drops two of the 680i SLI's USB ports and one of its Gigabit Ethernet controllers. Losing that second networking controller also costs the LT support for DualNet teaming, which allows two GigE connections to be combined into a single, pseudo-2Gbps link on the standard nForce 680i SLI.


With those relatively basic limitations, the LT chipset looks like little more than a watered down nForce 680i SLI. In fact, the chipset even reports itself to CPU-Z as a 680i SLI—no LT. Curious to see whether Nvidia is actually using the same chips as its 680i SLI reference board, we popped a few heatsinks and were surprised to discover different chips. The nForce 680i LT SLI, for example, is made up of an nForce 570 SLI MCP (presumably with one GigE controller and a couple of USB ports disabled), and a north bridge chip labeled C55-P-N-A2. That differs from the vanilla nForce 680i SLI, which is made up of an nForce 590 SLI MCP and a north bridge labeled C55-SLIX16N-A2.


This is just the latest example of Nvidia juggling chipset components for specific market segments, and there's really nothing wrong with the practice. In fact, it's fascinating to watch just how many different applications Nvidia can squeeze from a single MCP chip. However, we could do without the constant renaming. Nvidia officially lists the LT's south bridge component as the nForce 680i LT SLI MCP, but when the chip clearly bears the markings of an nForce 570 SLI MCP, calling it a 680 for the purpose of branding and segmentation seems a little silly.

Anyway, back to the motherboard.

CPU support LGA775-based Celeron, Pentium 4/D, Core 2 processors
North bridge Nvidia nForce 680i SLI LT SPP
South bridge Nvidia nForce 680i SLI LT MCP
Interconnect DMI (2GB/s)
Expansion slots 2 PCI Express x16
2 PCI Express x1
2 32-bit/33MHz PCI
Memory 4 240-pin DIMM sockets
Maximum of 8 GB of DDR2-400/533/667/800 SDRAM
Storage I/O Floppy disk
1 channel ATA/133
6 channels Serial ATA with RAID 0, 1, 0+1, 5 support
Audio 8-channel HD audio via nForce 680i and Realtek ALC885 codec
Ports 1 PS/2 keyboard
1 PS/2 mouse
4
USB 2.0 with headers for 4 more
1 RJ45 10/100/1000
1 1394a Firewire via Texas Instruments TSB43AB22A with headers for 1 more

1 analog front out
1 analog bass/center out
1 analog rear out
1 analog surround out
1 analog line in
1 analog mic in
1 TOS-Link digital S/PDIF output
BIOS Award
Bus speeds FSB: 400-2500MHz in 1MHz increments
DRAM: 400-1400MHz in 1MHz increments
PCIe 1: 100-200MHz in 1MHz increments
PCIe 2: 100-200MHz in 1MHz increments
SPPMCP ref clock: 200-400MHz in 1-2MHz increments
Bus multipliers SPPMCP: 1x-5x
Voltages CPU: 0.8-1.6V in 0.00625V increments
DRAM: 1.8-2.5V in 0.1V increments
FSB: 1.2-1.4V in 0.1V increments
SPP: 1.2-1.4V in 0.1V increments
Monitoring Voltage, fan status, and temperature monitoring
Fan speed control CPU, SYS, AUX, nForce

The spec sheet for Nvidia's nForce 680i LT SLI motherboard doesn't offer much in the way of surprises. As with the company's initial 680i SLI design, you won't find any auxiliary storage controllers or networking chips on this latest LT. Virtually every onboard peripheral can be traced back to the chipset.

About the only peripheral Nvidia hasn't integrated into its chipsets is Firewire. Instead, they've tapped Texas Instruments' TSB43AB22A 1394a controller to provide a couple of Firewire ports. Nvidia also calls on a third-party chip to handle audio codec duties, and as one might expect, that chip bears the infamous Realtek crab. The ALC885 isn't Realtek's fanciest HD audio codec, but it's the very same chip found on the initial nForce 680i SLI board design.