Nvidia’s nForce 680i LT SLI motherboard

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.

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.

Nvidia’s first attempt at a retail motherboard design used a black PCB to attract enthusiasts looking for a little visual flair. This latest LT, however, uses a plain green board that more closely resembles the reference designs we’re used to seeing.

Interestingly, Nvidia hasn’t changed the board layout much for the LT. That’s generally a good thing, since the initial 680i SLI board design was nearly spot-on. Just look at how both of the power connectors are neatly placed along edges of the board, so power cables won’t crowd the CPU socket. Someone’s been paying attention to our mobo reviews.

There’s plenty of room around the CPU socket for larger coolers, thanks in part to Nvidia’s decision to ring the socket with shorter capacitors. The board also has a couple of passive VRM coolers that should help dissipate the extra heat created by enterprising overclockers.

Presumably in an attempt to cut costs, Nvidia has elected to go with active chipset cooling on its LT motherboard. The north bridge chip is capped with a relatively low-profile heatsink that Nvidia has topped off with a fan that’s entirely too loud for a $200 motherboard. Seriously, plenty of mobos in this price range make do with passive chipset cooling, including those based on the nForce 680i SLI chipset. Nvidia shouldn’t have to resort to whiny chipset fans.

Apparently giving us one noisy chipset fan wasn’t enough; the south bridge also sports an active chipset cooler. By now, I’m sure it’s clear that we’re not huge, er, fans of active chipset cooling. Initial fan whine is one issue, but we’ve also found that the tiny fans commonly used in chipset coolers tend to get much louder over time. Those fans tend to fail abruptly, as well—a problem you don’t encounter with passive designs that lack moving parts.

At least the south bridge cooler is short enough to leave plenty of clearance for longer graphics cards, including Nvidia’s own GeForce 8800 GTX. Nvidia has taken special care to ensure that longer double-wide graphics cards won’t block access to any storage ports, which are neatly lined up along the edge of the board.

While the nForce 680i SLI board design features a third PCI Express x16 slot ostensibly meant for future physics products, that slot is missing from the LT. That leaves the board with pairs of PCI, PCIe x1, and PCIe x16 slots, which should be more than enough for most folks. We do wish that the board’s second PCIe x1 slot were moved down one place into the vacant space left by the missing x16 slot, though. Then double-wide graphics cards installed in the primary x16 slot wouldn’t block an x1 slot.

Without a parallel port, serial port, or secondary Ethernet jack at the rear, the 680i LT’s port cluster looks a little bare. Nvidia has populated it with the essentials, including Firewire, six analog audio outputs, and a TOS-Link digital S/PDIF output. There are four USB ports, as well, with headers for an additional four ports onboard.

BIOS options and software
Although Nvidia has dropped a number of features found on the nForce 680i SLI from this latest LT design, the board’s BIOS remains generally intact—and that’s a good thing.

First, the BIOS offers control over the CPU multiplier. This multiplier control even works for standard Core 2 processors, although you can only adjust the multiplier down with those chips. You’ll need an unlocked “Extreme Edition” CPU if you want to raise the multiplier beyond its default value.

Once you’ve settled on a multiplier, you can turn your attention to the board’s front-side and memory bus tweaking options. Quad-pumped front-side bus speeds are available between 400 and 2500MHz in 1MHz increments, and you can set target memory bus speeds between 400 and 1400MHz with the same granularity.

On the voltage front, the BIOS will let you crank a Core 2 processor up to 1.6V—0.2V short of the maximum CPU voltage available with the standard nForce 680i SLI BIOS. The LT manages to match its predecessor’s support for memory voltages up to 2.5V. However, you don’t get access to the interconnect or south bridge voltage options present in the standard 680i SLI BIOS.

Things even out when we look at memory options, which are virtually identical between the LT and standard 680i SLI. Keep in mind that the LT only supports Enhanced Performance Profiles up to 800MHz, though.

Nvidia cuts one last corner on the fan speed front, dropping temperature-based fan speed control for the chassis fan. You do get automatic fan speed control for the CPU fan header, but are only able to tweak fan speeds manually for the rest. That’s a little disappointing in light of the LT’s active chipset coolers, which should only spin up to full speed when the chipset gets hot enough to need the extra cooling.

We can only hope Nvidia adds automatic chipset fan speed control to the LT’s BIOS. A BIOS update should be coming, if only to complete the board’s support for Nvidia’s own nTune system utility.

In its current state, the 680i LT’s BIOS doesn’t support nTune voltage or fan speed manipulation. We’ve long chided third-party motherboard makers for not including the necessary BIOS hooks to fully exploit nTune’s capabilities, so Nvidia certainly doesn’t get off the hook here.

At least they’ve included all the hooks necessary for nTune’s monitoring app, which tracks a wide range of system variables. This ability to track system variables is handy, but the real draw is being able to use changes in some of those variables to launch different system setting profiles via nTune’s custom rules wizard.

Our testing methods
We’ll be comparing the performance of Nvidia’s nForce 680i LT SLI motherboard to that of EVGA’s rebadged nForce 680i SLI reference design and to a couple of nForce 600-series boards from Asus. Since a number of Nvidia’s partners will be offering essentially the same LT board, we’ll be referring to it with a more generic Nvidia nForce 680i LT SLI name in our graphs. The board we tested will appear on store shelves as the EVGA 122-CK-NF67.

All tests were run at least twice, and their results were averaged, using the following test systems.

Thanks to Corsair for providing us with memory for our testing. 2GB of RAM seems to be the new standard for most folks, and Corsair hooked us up with some of its 1GB DIMMs for testing.

Also, all of our test systems were powered by OCZ GameXStream 700W power supply units. Thanks to OCZ for providing these units for our use in testing.

We used the following versions of our test applications:

• SiSoft Sandra Standard 2007 SR1
• WorldBench 5.0
• TCD Labs HD Tach v3.01
• Futuremark 3DMark06 Build 1.02
• Splinter Cell Chaos Theory v1.05
• RightMark Audio Analyzer 5.5
• RightMark 3D Sound 2.3
• NTttcp
• Cinebench 9.5
• Sphinx 3.3
• Quake 4 1.30
• F.E.A.R. 1.08

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Memory performance

The nForce 680i LT pulls up a little slow in our first wave of memory subsystem tests, failing to equal the performance of even Asus’ budget-minded P5N-E SLI.

Motherboards don’t always handle four-DIMM configurations well, so we popped in an extra couple of memory modules to look for problems. We had to slow the P5N-E’s DRAM command rate to 2T to get four DIMMs running stable on that board. The others had no problem running a tighter 1T command rate with four DIMMs.

Adding a couple of DIMMs doesn’t help the LT much, even against a P5N-E with a 2T command rate. Small differences in memory subsystem performance may not lead to significant differences in application performance, though.

WorldBench

In WorldBench, the LT has no problem keeping up with its big brother, EVGA’s 680i SLI-based 122-CK-NF68. Both are a little faster than the Asus offerings.

Gaming

Our first round of game tests don’t really favor one board over another, although Quake 4 does see the LT lagging behind the Asus boards just a little. Still, it’s a little faster there than the 122-CK-NF68.

Multi-GPU gaming performance
Our first round of gaming tests was conducted with lower in-game detail levels and display resolutions, but we’ve cranked things up for a second round. These tests use high resolutions, high detail levels, and anisotropic filtering and antialiasing. We’ve tested each board with a single GeForce 7900 GTX, and then conducted a second round of tests with two 7900 GTXs running in SLI.

This second round of game tests is largely bound by the graphics card, as most real-world gameplay scenarios are. This is where the nForce 680i’s dual 16-lane PCI Express x16 slots should give it an advantage over the P5N-E SLI, whose 650i chipset can only offer eight lanes per card in SLI configurations. However, only 3DMark06’s Shader Model 2.0 score shows a notable difference in performance between dual-x8 and dual-x16 SLI implementations.

Cinebench rendering

Cinebench scores are close across the board.

Sphinx speech recognition

The LT lags behind in Sphinx, though. We’ve found this speech recognition engine to be particularly sensitive to memory subsystem performance, so it’s no surprise to see the LT bringing up the rear. It really isn’t that much slower than the Asus boards, though.

Audio performance

Although it dabbled in hardware acceleration for 3D audio in the past, these days Nvidia has relinquished responsibility for positional audio to codec manufacturers. 3D audio calculations are performed in the codec driver, and performance generally depends on whose codecs you’re using. The nForce 680i LT reference design features a Realtek codec, so its performance in RightMark’s 3D audio tests closely matches that of other Realtek-based boards. Asus’ Striker Extreme enjoys much lower CPU utilization thanks to its use of a codec chip and drivers from Analog Devices.

We should also note that some of Realtek’s HD audio drivers fail to correctly implement EAX occlusions and obstructions, rendering some games virtually unplayable with EAX effects enabled.

Audio quality
We used an M-Audio Revolution 7.1 sound card for recording in RightMark’s audio quality tests. Analog output ports were used on all systems. To keep things simple, I’ve translated RightMark’s word-based quality scale to numbers. Higher scores reflect better audio quality, and the scale tops out at 6, which corresponds to an “Excellent” rating in RightMark.

The nForce 680i LT SLI’s performance in RightMark Audio Analyzer is unremarkable, but no worse than that of either Asus board. Interestingly, though, the LT does score lower than the EVGA-branded nForce 680i SLI in a couple of tests.

ATA performance
ATA performance was tested with a Seagate Barracuda 7200.7 ATA/133 hard drive using HD Tach 3.01’s 8MB zone setting.

ATA performance doesn’t really vary from board to board.

Serial ATA performance
Moving to Serial ATA, we tested performance with a Western Digital Raptor WD360GD SATA hard drive. Again, we used HD Tach 3.01’s 8MB zone test.

The LT’s Serial ATA performance is consistent with that of other 680i-based motherboards.

USB performance
Our USB transfer speed tests were conducted with a USB 2.0/Firewire external hard drive enclosure connected to a 7200RPM Seagate Barracuda 7200.7 hard drive. We tested with HD Tach 3.01’s 8MB zone setting.

Nvidia has never had a problem with USB performance, so it’s no surprise to see the LT matching the transfer rates and CPU utilization of 680i SLI boards from Asus and EVGA.

Firewire performance
Our Firewire transfer speed tests were conducted with the same external enclosure and hard drive as our USB transfer speed tests.

Unfortunately, the LT board’s Firewire chip is a little slow in HD Tach’s write speed test. Its performance does match what you get with the pricier EVGA 122-CK-NF68, though.

Ethernet performance
We evaluated Ethernet performance using the NTttcp tool from Microsoft’s Windows DDK. The docs say this program “provides the customer with a multi-threaded, asynchronous performance benchmark for measuring achievable data transfer rate.”

We used the following command line options on the server machine:

ntttcps -m 4,0,192.168.1.25 -a

..and the same basic thing on each of our test systems acting as clients:

ntttcpr -m 4,0,192.168.1.25 -a

Our server was a Windows XP Pro system based on Asus’ P5WD2 Premium motherboard with a Pentium 4 3.4GHz Extreme Edition (800MHz front-side bus, Hyper-Threading enabled) and PCI Express-attached Gigabit Ethernet. A crossover CAT6 cable was used to connect the server to each system.

The boards were tested with jumbo frames disabled.

Nvidia didn’t strip TCP/IP checksum offloads from the LT, so the board’s CPU utilization with Gigabit Ethernet transfers is quite reasonable. Throughput is beyond reproach, as well, although you only get it through one network connection.

Power consumption
We measured system power consumption, sans monitor and speakers, at the wall outlet using a Watts Up power meter. Power consumption was measured at idle and under a load consisting of a multi-threaded Cinebench 9.5 render running in parallel with the “rthdribl” high dynamic range lighting demo.

Apparently, the features Nvidia left on the cutting room floor to create the nForce 680i LT SLI didn’t take any wattage with them. In fact, the board consumes slightly more power than the standard nForce 680i SLI, perhaps in part because of the power draw associated with active chipset cooling.

Overclocking
For our overclocking tests, we swapped out our Core 2 Duo E6600 engineering sample in favor of a retail E6300. We’ve had this chip running stable at up to 3.3GHz without extra voltage or cooling, so it should give the LT plenty of opportunity to shine.

And shine it does. After dropping the CPU multiplier to 6X, we were able to push the board to a stable front-side bus speed of 480MHz—just short of the 490MHz we achieved with the nForce 680i SLI reference design. Apparently, the difference between the nForce 680i SLI’s “best” overclocking and the LT’s “good” is about 10MHz.

While a 480MHz front-side bus speed is certainly impressive, it’s not entirely uncommon for a board based on a 600-series chipset. We’ve had Asus’ 680i SLI-based Striker Extreme up to 480MHz and Asus’ 650i-based P5N-E SLI up to 470MHz.

Conclusions
Nvidia has succeeded in creating a more affordable motherboard design with the nForce 680i LT SLI, but they’ve had to perform relatively major surgery to get the board under $200. We can live without some of the amenities that have been cut, such as EPP memory support beyond 800MHz and a couple of USB ports. Given our review sample’s ability to run a 480MHz front-side bus, we’re not too worried that Nvidia only rates the LT’s overclocking potential as “good,” either.

Unfortunately, a couple of Nvidia’s LT amputations are harder to swallow. The lack of a second Gigabit Ethernet port is puzzling at best—and practically inexcusable for a $200 motherboard. Few users may actually need that second networking port, but with virtually every $200 board sporting dual GigE options, the LT starts to look a little stingy.

That’s not the worst of it, though. The LT’s active chipset coolers are easily the board’s most disappointing features. Intricate arrays of heatpipes and passive coolers are all the rage these days, and although we don’t insist on an ornate cooling apparatus, a $200 motherboard should at the very least offer quiet chipset cooling. With a pair of chipset fans that lack temperature-based fan speed control, the LT’s chipset cooling solution is neither elegant nor quiet.

Now, just because Nvidia chose to cut corners in the cooling department doesn’t mean that other board vendors have to as well. While EVGA, XFX, and others will be offering rebadged reference boards, the LT will also be available as a chipset, so it’s possible that some motherboard makers will roll their own custom designs. Those designs will have to at least incorporate better chipset cooling to be competitive in a market laced with dual-slot P965 and 975X boards selling for less than $200. But the LT boasts SLI support that you don’t get with Intel chipsets—and with a full 16 lanes of bandwidth to each card—so it does have a leg up in the multi-GPU arena. We’re just not sure how many mobo makers are going to want to invest board design resources for a chipset that’s so similar to the existing nForce 680i SLI.

In the end, then, the nForce 680i LT SLI turns out to be a bit of a disappointment. The board’s performance may stand up to that of other $200 offerings, but its features do not. So this is not a tribute to football legend Lawrence Taylor, then. Perhaps the LT stands for Lesser Technology, instead.