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MSI's K8N Diamond Plus motherboard


X16 gets an Audigy
— 12:00 AM on March 23, 2006

ManufacturerMSI
ModelK8N Diamond Plus
Price (Street)
AvailabilityNow

SEEMINGLY CONTENT TO MAKE DO with the original nForce4 SLI, motherboard manufacturers have been slow to adopt NVIDIA's nForce4 SLI X16 chipset. For months, Asus' A8N32-SLI was the only Socket 939 motherboard capable of feeding 16 lanes of PCI Express to each of a pair of graphics cards in SLI, giving enthusiasts seeking gobs of graphics bandwidth few options. Fortunately, that's starting to change. Mobo makers appear to be warming to the X16 chipset, and MSI is the latest to take the plunge with the K8N Diamond Plus.

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

CPU supportSocket 939-based Athlon 64 processors
North bridgeNVIDIA C51D
South bridgeNVIDIA nForce4 SLI
InterconnectHyperTransport (8GB/sec)
Expansion slots2 PCI Express x16
1 PCI Express x4
2 PCI Express x1
2 32-bit/33MHz
Memory4 184-pin DIMM sockets
Maximum of 4GB of DDR266/333/400 SDRAM
Storage I/OFloppy disk
2 channels ATA/133 with RAID 0, 1, 0+1 support
4 channels Serial ATA with RAID 0, 1, 0+1, 5 support
2 channels Serial ATA with RAID 0, 1 support via SiI 3112
Audio8-channel HD audio via Creative Sound Blaster Audigy SE
Ports1 PS/2 keyboard
1 PS/2 mouse
1 serial port
1 parallel port
4
USB 2.0 with headers for 6 more
1 Firewire via VIA VT630 with header for 2 more
1 RJ45 10/100/1000
1 RJ45 10/100/1000 via Marvell 88E8053


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 coaxial digital S/PDIF input
1 coaxial digital S/PDIF output
BIOSAMI BIOS
Bus speedsHT: 200-450MHz in 1MHz increments
HT multipliers: 1X-5X
PCI-E: 100-148MHz in 1MHz increments
Interconnect: 200, 400, 600, 800, 1000MHz
Bus dividersDRAM/HT: 1/2, 2/3, 5/6, 5/4, 1/1
VoltagesCPU: auto, 0.8-1.55V in 0.025V increments
CPU overvolt: +0.05-0.75V in 0.05 increments
DDR: 2.6-4.1V in 0.05V increments
PCI-E: 1.5-1.85 in 0.05V increments
North bridge: 1.2-1.5 in 0.1V increments
MonitoringVoltage, fan status, and temperature monitoring
Fan speed controlCPU, north bridge

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.