MSI’s K8N Diamond Plus motherboard

Like most enthusiast boards, the K8N Diamond Plus comes loaded with features, including dual Gigabit Ethernet options, two flavors of Serial ATA RAID, and a BIOS filled with tweaking, overclocking, and even fan speed controls. MSI has also fitted the board with a Sound Blaster Audigy chip that promises support for EAX Advanced HD and better audio quality than typical motherboard audio implementations.

Is the K8N Diamond Plus’ integrated Audigy audio really all that, and more importantly, can the board keep up with the latest nForce4 SLI, X16, and even CrossFire boards on the market? Let’s find out.

The specs

The K8N Diamond Plus comes loaded with everything you’d expect from a high-end board, including a whopping 38 lanes of PCI Express. 18 of those lanes can be found on the chipset’s north bridge, which reserves 16 lanes for the motherboard’s primary PCI-E x16 slot. The remaining 20 lanes are on the south bridge, where 16 are consumed by the second x16 slot. That leaves a total of six PCI Express lanes up for grabs—two at the north bridge and four at the south bridge. The extra north bridge lanes are consumed by one of the PCI-E x1 slots and the Marvell 88E8053 Gigabit Ethernet controller, while the second x1 slot, Silicon Image 3132 SATA controller, and x4 slot are fed by the south bridge. However, the south bridge has just four lanes of PCI-E bandwidth to spare, so the x4 slot actually only gets two lanes of bandwidth.

Because its PCI Express lane distribution splits graphics cards in SLI between north and south bridge chipset components, some have charged that the nForce4 SLI X16’s chipset interconnect could bottleneck performance. The interconnect is a 16-bit/1GHz HyperTransport link that provides 8GB/s of bandwidth—just enough to fully saturate one PCI Express x16 slot. Once you throw in additional south bridge I/O traffic, things get a little more crowded. However, it’s important to note that the nForce4 SLI X16’s chipset interconnect provides just as much bandwidth between its north and south bridge components as the chipset has between itself and the Athlon 64 processor. Consolidating enough PCI Express lanes at the north bridge for two graphics cards is undoubtedly a more elegant approach, and one that ATI employs with its Radeon Xpress 3200, but that doesn’t necessarily mean that NVIDIA’s implementation is any slower in the real world.

Given the nForce SLI X16’s abundance of south bridge I/O components, it’s no surprise there are concerns about interconnect bandwidth. Of those components, the south bridge’s Gigabit Ethernet and ATA and RAID controllers are the most notable. And then there are the auxiliary GigE and Serial ATA RAID controllers. Both of those chips ride the PCI Express bus, so they won’t contend for PCI bandwidth.

With auxiliary storage and networking controllers riding the PCI Express bus, the K8N Diamond Plus’ only PCI-based peripherals are its VIA VT6306 Firewire chip and a Sound Blaster Audigy SE. This is the first mobo we’ve encountered with an Audigy SE onboard, but unfortunately, the Special Edition appears to be of the short bus variety. Despite appearing as an Audigy in Windows’ Device Manager, the chip is actually a Creative CA0106-DAT. We’ve seen the same chip on other boards, but in those cases, it identified itself as a Sound Blaster Live! 24-bit. Adding to the intrigue, the K8N Diamond Plus ships with a Creative Live! 24-bit driver CD, which must be used to install the “Audigy” drivers for the board.

Regardless of its true origins, the Audigy SE claims to support high-definition audio and EAX Advanced HD. It doesn’t appear to accelerate positional 3D audio in hardware, though.

The board
The K8N Diamond Plus’ veritable cornucopia of peripheral chips, slots, and ports look great on the spec sheet, but squeezing them all onto a standard ATX form factor isn’t easy. Fortunately, MSI has done a pretty good job with the layout, even if it looks a little crowded from above.

We’re not thrilled with the position of some of the board’s power connectors, though. The 24-pin primary power connector is located along the right edge near the top of the board, just where we like it. However, the eight-pin auxiliary 12V connector is far enough down the left side of the board to create cable clutter around the CPU socket. Cable clutter can restrict air flow around the processor heat sink, potentially raising CPU temperatures in the process.

Despite its eight-pin power plug, the K8N Diamond Plus works just fine with older four-pin ATX 12V power connectors. The board also has a four-pin Molex connector above the top PCI Express x16 slot, but it’s only needed when running a pair of graphics cards in SLI.

As if cable clutter around the CPU weren’t enough, the K8N Diamond Plus’ north bridge cooler leaves little room between itself and the socket. The cooler is close enough to create clearance problems with wider processor heat sinks like Zalman’s CNPS7700, although there’s enough room for the slimmer CNPS9500. Given that MSI appears to have taken great care in ensuring that only low-profile capacitors surround the CPU socket, it’s particularly disappointing to see the north bridge cooler get in the way.

Were the cooler a fanless design, it might be easier to forgive. But it’s not. Despite a fancy heat pipe linking heat sinks on the north and south bridge chips, the cooler still relies on a tiny chipset fan to keep temperatures in check. We’d prefer passive chipset cooling, as smaller fans tend to develop increasingly annoying whines over time. The K8N Diamond Plus’ fan could be an exception, of course, but it’s rare to see generic chipset fan maintain reasonable noise levels with extended use.

The chipset cooler’s saving grace is its low-profile south bridge component, which leaves plenty of clearance for longer graphics cards. Even the heat pipe is carefully shaped to avoid conflict with PCI Express cards, and the K8N Diamond Plus can support a bunch of them. You see, in addition to a pair of standard x16 slots, the board’s yellow PCI-E x4 slot has also been notched to accept longer x16 graphics cards. Cards installed in the slot obviously won’t benefit from a full 16 lanes of bandwidth, and they won’t be able to accelerate 3D graphics as part of a three-card SLI configuration, but users should at least be able to squeeze a couple of extra monitor outputs from the slot.

Although the K8N Diamond Plus’ array of PCI Express slots is certainly generous, the board has only two standard PCI slots. With a double-wide SLI configuration, one of those PCI slots will be blocked, leaving only one slot available for audio cards, TV tuners, and the like. Double-wide SLI configurations will leave two PCI Express slots open, but given the dearth of PCI Express peripherals, we’d almost prefer that one of those slots be plain old PCI. We’d really rather have a wider selection of PCI Express x1 peripherals so we could ditch PCI completely, though.

Moving to the right, we see the K8N Diamond Plus’ Serial ATA ports all neatly arranged along the edge of the board. This is exactly where they should be, and although gargantuan secondary graphics cards like the GeForce 7900 GTX can crowd the ports a little, they should all still be usable.

Speaking of ports, the K8N Diamond Plus’ backplane is loaded. Here, you’ll find a handful of legacy ports in addition to plenty of USB, Ethernet, analog audio, and even Firewire. MSI has also equipped the board with coaxial and TOS-Link S/PDIF outputs for those with digital speakers or receivers, but there’s no provision for digital audio input.

If there aren’t enough ports on the backplane for your stack of Firewire and USB peripherals, the K8N Diamond Plus also comes bundled with PCI brackets for an additional two Firewire and USB ports. There are onboard headers for four more USB ports on top of that, too.

The BIOS and nTune support
While the K8N Diamond Plus is stacked with features and peripherals, the BIOS will have to be just as well equipped to cater to enthusiasts and overclockers.

Things start well enough, with the BIOS offering full control over a laundry list of Athlon 64 memory controller timings. There are just enough options to get you into trouble if you don’t know what you’re doing.

Speaking of trouble, the BIOS also has an extensive array of overclocking options. Users can crank the HyperTransport clock all the way up to 450MHz, but at those speeds, the fact that the BIOS’s CPU multiplier only goes down to 8x could be a problem. That’s a shame, as MSI hasn’t skimped in the voltage department. CPU voltages are available as high as 2.3V, and it’s possible to crank the memory up to an impressive 4.1V with an onboard jumper switch.

We’ve been around long enough to prefer overclocking the old fashioned way, but the K8N Diamond Plus also has a couple of automatic overclocking options for those seeking something a little simpler. Dynamic overclocking kicks in when the CPU is under load, and users can set it to increase speeds by between 1% and 15%. The BIOS also allows users to overclock select NVIDIA graphics cards by similar percentages. Most importantly, though, all automatic overclocking options are disabled by default.

Unfortunately, not all of the BIOS defaults are correct. The 1.00 revision of the BIOS incorrectly sets a slower HyperTransport link between the chipset’s north and south bridge components. It’s easy to bump this connection up to full speed, and MSI has corrected the problem in a beta BIOS it released to us for testing.

Moving along, the K8N Diamond Plus’ BIOS offers a pretty decent array of automatic fan speed control options. Users can set temperature targets for the CPU and north bridge fans, but sadly, there’s no fan speed control for the board’s system fan headers. The BIOS also lacks fan failure or temperature-based shutdown and alarm conditions.

Users can get their hands on fan speed and temperature-based alarm conditions by installing MSI’s CoreCenter Windows software, though.

Otherwise, CoreCenter is more of a glorified hardware monitoring app than a BIOS extension. It’s possible to adjust the level of dynamic overclocking, but serious overclockers will want to stick with the BIOS, especially since the board’s support for nTune is among the worst we’ve seen.

In addition to lacking support for nTune’s hardware monitoring capabilities, the K8N Diamond Plus also lacks the hooks necessary to support the app’s overclocking and memory timing controls. About the only thing you can do with nTune is adjust graphics card clock speeds, which really have nothing to do with the motherboard. I guess MSI would rather you use CoreCenter to monitor and tweak the board, but since CoreCenter doesn’t match many of nTune’s features and capabilities, the user ends up losing out.

Our testing methods
Today we’ll be comparing the K8N Diamond Plus’ performance with that of DFI’s LANParty UT RDX200 CD-DR and LANParty UT NF4 SLI-DR Expert, ECS’s KA1 MVP Extreme, and Asus’ A8N32-SLI and A8R-MVP.

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.

Our test systems were powered by OCZ PowerStream power supply units. The PowerStream was one of our Editor’s Choice winners in our latest PSU round-up.

We used the following versions of our test applications:

• SiSoft Sandra Standard 2005 SR3
• WorldBench 5.0
• TCD Labs HD Tach v3.01
• Futuremark 3DMark06 Build 1.02
• DOOM 3
• Far Cry v1.3
• Splinter Cell Chaos Theory v1.05
• RightMark Audio Analyzer 5.5
• RightMark 3D Sound 2.1
• NTttcp
• Cinebench 2003
• Sphinx 3.3

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. Most of the 3D gaming tests used the Medium detail image quality settings, with the exception that the resolution was set to 640×480 in 32-bit color.

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

As usual, performance in our memory subsystem tests is pretty close. Any variation here is a result of how each board manufacturer has chosen to tune the Athlon 64’s on-die memory controller. Some are more aggressive than others, as evidenced by the scores from NF4 SLI-DR Expert, but that board’s tighter timings limit its compatibility with generic memory modules. The K8N Diamond Plus suffers no such compatibility problems, as its default memory timings are more conservative.

WorldBench

WorldBench is a wash, with five of six boards offering identical scores.

Gaming

The K8N Diamond Plus bounces around in our low-resolution gaming tests. Overall, it’s about as fast as the rest of the pack.

SLI gaming performance
Our first round of gaming tests were conducted with low 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, so they should be fairly indicative of how gamers play in the real world. We’ve tested each board with a single GeForce 7800 GTX, and we’ve also benchmarked the Asus A8N32-SLI, DFI LANParty UT NF4 SLI-DR Expert, and MSI K8N Diamond Plus with a pair of 7800 GTXs running in SLI. We’ve also tested the KA1 MVP, RDX200, and A8R-MVP with single and dual Radeon X850 XT cards using ATI’s Catalyst 6.1 graphics drivers.

When looking at our SLI performance results, pay special attention to the jump in performance from single- to multi-card configurations. We’re not out to compare the Radeon X850 XT’s performance with that of the GeForce 7800 GTX; we just want to see how adding a second card can improve overall performance.

With high resolutions, detail levels, and antialiasing and aniso bottlenecking performance at the graphics card, the K8N Diamond Plus has no problem keeping up with other SLI implementations.

Cinebench rendering

Nothing to see here. Move along.

Sphinx speech recognition

Sphinx is particularly sensitive to memory bandwidth and latency, so it’s no surprise to see the aggressively-timed DFI board edge out the others. The K8N Diamond Plus does well to keep up with the rest of the field.

Audio performance

So much for the onboard Audigy. Although the K8N Diamond Plus’ audio chip supports more simultaneous DirectSound voices than the other onboard audio implementations, CPU utilization is nothing special. In fact, with EAX enabled, the K8N Diamond Plus’ Audigy has higher CPU utilization than boards using Realtek’s software audio drivers.

To be fair, we’ve encountered numerous positional audio problems with EAX and Realtek’s audio drivers. The Audigy’s higher CPU utilization here may simply be due to the fact that it’s doing EAX correctly. We’d prefer that the chip could do it correctly in hardware, though.

Audio quality
We used an M-Audio Revolution 7.1 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.

With the exception of the Total Harmonic Distortion test, the K8N Diamond Plus’ Audigy fares reasonably well in RightMark Audio Analyzer. To my ears, it sounds a little brighter than typical onboard audio implementations, with less of the muffled flatness that tends to plague Realtek audio.

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.

The K8N Diamond Plus’ ATA performance is about what we’d expect from the nForce4 SLI X16 chipset.

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.

Everything’s pretty even in our Serial ATA performance tests, as both of the K8N Diamond Plus’ SATA controllers are competitive.

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.

MSI does well in our USB performance tests, especially when you consider the K8N Diamond Plus’ low CPU utilization.

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

Firewire performance is pretty even across the board, at least when you look at the top competitors, which include the K8N Diamond Plus.

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 nForce4 boards were tested with the NVIDIA Firewall and Jumbo Frames disabled.

NVIDIA recently confirmed that it had scaled back ActiveArmor Gigabit Ethernet acceleration in its latest nForce drivers, and we can see that in action here. The K8N Diamond Plus’s GigE CPU utilization isn’t as low as we’ve seen from the nForce4 before, but NVIDIA says that scaling back the offload engine was the only way to avoid data corruption issues that had plagued ActiveArmor in the past. NVIDIA’s so confident that it’s banished those data corruption issues for good that it’s actually enabling ActiveArmor by default in the latest drivers.

Even with ActiveArmor’s reduced effectiveness, the K8N Diamond Plus’s nForce4 GigE controller still uses fewer CPU resources than the board’s Marvell Gigabit chip. Throughput is excellent for both chips, too.

Overclocking
For our overclocking tests, we swapped in a pair of OCZ Platinum Rev 2 DDR400 memory modules and set them to run at 2.5-4-4-8-1T timings. These DIMMs use Samsung TCCD memory chips and have proven to be great overclockers in the past. We also backed off on our CPU and HyperTransport processor link multipliers to remove them as potential bottlenecks, and nudged the memory voltage up to 2.8V.

With the memory divider set to 1:1, we were able to get the K8N Diamond Plus stable with a 280MHz HyperTransport clock.

280MHz isn’t spectacular, but it’s the highest overclock we’ve been able to squeeze from these DIMMs. Besides, we weren’t done yet. To remove the memory as a potential bottleneck, we backed off on the memory divider and cranked the HT clock a little higher.

20MHz later, we settled on a 300MHz HyperTransport clock. The board was perfectly stable at this speed, but we couldn’t get it to post with a 310MHz HT clock. Not even MSI’s latest beta BIOS could coax 310MHz from the board, and neither could an array of voltage tweaks. That might not be entirely the board’s fault, though. Because the BIOS’ lowest CPU multiplier is 8x, our Athlon 64 FX-53 processor was forced to run above stock speeds with an HT clock higher than 300MHz. This FX-53 is an early sample, and it’s never been particularly comfortable running faster than its default 2.4GHz clock speed.

If MSI wants the K8N Diamond Plus to appeal to more extreme overclockers, it really needs to offer lower CPU multipliers in the BIOS. The board could be capable of HyperTransport speeds well in excess of 300MHz, but without lower CPU multipliers, many users’ CPUs may have a hard time keeping up.

Conclusions
With a street price as low as $180, the K8N Diamond Plus sells for about as much as other nForce4 SLI X16-based motherboards on the market. Its features are pretty comparable, as well, with most manufacturers relying on the same auxiliary Silicon Image Serial ATA RAID and Marvell Gigabit Ethernet chips. The K8N Diamond Plus does have a few unique tricks up its sleeve, though. It’s the only Socket 939 board we’ve seen that supports up to three PCI Express x16 graphics cards, and even if the third card can’t contribute to SLI, it could be useful for those seeking more than four monitor outputs. The K8N is also the first board we’ve seen with a Creative Audigy SE onboard, although the chip’s lack of hardware acceleration for 3D audio limits its appeal.

Apart from the Audigy SE’s lack of hardware acceleration for 3D audio—an omission that’s hard to harp on given the complete lack of hardware-accelerated 3D audio on Athlon 64 motherboards—our only real gripe with the K8N Diamond Plus is the board’s active chipset cooler. The nForce4 chipset has a reputation for running a little hot, but other manufacturers have managed to reel in its thermals with passive cooling designs, and we wish MSI could do the same. At the very least, it would be nice if the cooler didn’t encroach on the area around the CPU socket.

Overall, MSI has built a solid nForce4 SLI X16 motherboard with the K8N Diamond Plus. The board has plenty of extra peripherals, a decent array of BIOS tweaking and overclocking options, and enough unique flair to set itself apart from other offerings on the market. It’s not perfect, mind you, but it’s little more than a nip and tuck away from greatness.