Recently, we've looked at MSI's nForce 570 SLI based K9N Platinum motherboard. It was an excellent performer, and for the majority of folks, provided just about enough features any consumer would need. Of course, enthusiasts are a fickle bunch and having just the necessities often isn't enough.
The MSI K9N Diamond motherboard we'll be reviewing today is based on NVIDIA's "enthusiast gamer" minded nForce 590 SLI for AMD's AM2 CPUs. Along with all of the features missing from the 570 SLI, such as LinkBoost, SLI-Ready memory support and dual 16x PCI Express pathways, MSI throws in Creative's Sound Blaster Live! onboard for the audio chores.
The MSI K9N Diamond Motherboard
MSI includes a nicely designed user manual that covers most of the basics. It doesn't go into great detail in the BIOS area other than mentioning the function of each BIOS page, so I guess they leave it up to the tweaker to explore. They also include a handy quick install leaflet, driver disk and CD. Several SATA cables are included and they are both the ones with the 90° bend as well as traditional straight cables. I've always preferred these 90° connections as they are less likely to pop off if your case is cramped inside. MSI also includes rounded floppy and IDE cables in case you need them. A couple of rear brackets are included for extra USB and FireWire connections. The D-Bracket has both USB and LED diagnostic lights, which can be very useful if you're experience system issues.

MSI includes a SLI bridge as well as a PCI support bracket to help keep the bridge in place. For users on the move, this will prevent the bridge from shaking loose during transport. There is also a custom rear IO shield as standard shields that normally come included with PC cases will not fit.
Considering the number of features, the layout of the K9N Diamond isn't bad. As with the Platinum version of the K9N series, the Diamond features a black PCB. The CPU area is pretty clear of obstructions, and we managed to fit the gigantic Zalman AM2 CNPS9500 without any problems. We did not experience issues with the Zalman since the flat area faces the memory slots, but if your cooler flares towards the memory, it may be possible that you will lose the use of the DIMM slot(s) closest to the CPU socket. We don't have much of an inventory of AM2 performance coolers, but as long as the cooler follows AMD's specifications, you should be good to go.
Between the CPU socket and the rear IO are a series of capacitors and MOSFETs. Unlike some of MSI's past motherboards, they chose not to attach any heatsinks to this area. This is a bit surprising on their part, as the area did get fairly warm during testing. To the right is a four pin CPU fan header and to the left is the PWR3 connection which is used to supply additional power to the CPU. The Molex connection (PWR2) is used to provide additional power to the upper range of video cards and SLI.
Both the North and South bridge of the K9N Diamond are cooled with a heatpipe/active cooler. The fan itself is barely audible and noise should be a non-issue for the majority of folks.

The memory banks are coloured coded and the K9N Diamond officially supports DDR2-800 and lower. For dual channel, you will have to used match memory pairs in each channel bank (ex: DIMM 1+3 or DIMM 2+4).
While NVIDIA does spin the 590 SLI as having an enthusiast BIOS, MSI doesn't just stop there. Right next to the memory connections is the new . As before, this chip allows for a number of performance options that is custom to MSI.
Just below the memory slots is the PWR1 24-pin ATX power connection. You can use a 20-pin PSU, but for any high-end system, we would recommend against it. Just below the power connection is the IDE1 connection for legacy storage. Next to that is the floppy connection for the last 3 people on the planet who still uses these devices.
Six SATA connections are grouped together near the edge of the motherboard between the two PCI Express graphics slots. The great thing about this location is that it should minimize any issues one may have with cables interfering with long PCIE cards. The MSI K9N Diamond supports SATA-II, and with NVRAID, RAID 0, 1, 0+1, 5 and JBOD are all supported. These connections are SATA 3Gb/s compatible and backwards compatible with the older 1.5Gb/s spec.
In the event an overclocking adventure goes awry, the CMOS battery isn't in the most convenient of locations should you be using a long PCI Express card in PCI Express graphics slot #2. Right next to all of the SATA slots is a CMOS reset button which is in a better spot should you need to depress it.
Moving on to the peripheral slots, we can see the two PCI Express graphics (PEG) slots sandwiching two PCIE connections. The added space (two slots between the PEG slots) will allow for specialized cooling for SLI setups. Of course, you'll likely lose the use of the adjacent PCI and PCIE slots, but this will not be the case if you stick with single slot cooling. Next to the second PEG slot are two PCI slots for additional expansion.
Of all the recent 5xx series of nForce boards, the 590 SLI is the only model that offers dual x16. PEG #1 is a full x16 when used in single card mode.
Rounding things out are the external inputs and outputs. From left to right we have; two PS/2 ports, parallel, FireWire and serial connections, two Gigabit LAN, four USB and the 7.1 sound connections. While AC'97 may be just "good enough" for some, the MSI K9N Diamond comes with the Creative audio controller MSI has been adding in some of their recent premium boards.
The BIOS
Typically we're used to seeing the AWARD BIOS with MSI boards, but this particular one uses the just as popular AMI BIOS. Like most enthusiast boards, there are a large number of options for those who like to get their hands dirty in the BIOS. We'll skip directly to those areas since we figure most of you know how to fiddle with items like system time and boot order.

In the Advanced Chipset page, there are two options for Hyper Transport configuration. User configurable options for HT settings for the South Bridge to CPU are Enabled and Disabled. The HT MCP55 configuration has an option called MCP55 (SB) to C51 (NB) Frequency, where it starts at 200MHz and maxes out at 1000MHz.
The Cell Menu page is the central hub for the important system tweaks that are key in setting up a finely tuned box.

By default, AMD's Cool 'n' Quiet is disabled, which is where we suggest you leave it if the K9N Diamond is to be a workhorse PC or gaming rig. This feature lowers the power consumption and enables a quieter-running system when the CPU is less busy. The performance-on-demand feature of the technology basically allows the CPU to wake up into a more active state as the need arises. According to MSI, if you choose to use Cool 'n' Quiet, you must have memory occupying DIMM 1 for stability reasons.

The CPU Frequency default is 200.0 and has increment options of 0.5MHz. If you're uncomfortable, or impatient, you can forego the manual process and choose the CPU Dynamic Overclocking option. This is disabled by default, but you have six options ranging from 1% to 15%. This mode only kicks in when the CPU is under load. While it's idle, the CPU will run at its default speed but once you start any CPU intensive application, the motherboard will dynamically overclock based on the settings chosen.
The CPU Frequency Configuration (not to be confused with CPU Frequency) allows the user to enter a sub-menu and make adjustments to the CPU's ratio and voltage. The majority of CPUs are locked, except for FX chips, so this section may not be terribly useful if you're an owner of one of a non-FX AM2. That said, the options are there for the user to change.
The next section of the Cell Menu focusses on the memory. In order to make any user tweaks to the memory, you will need to set the Memclock Mode to Manual.

You'll be able to make adjustments to the memory's frequency, which is especially handy if you have memory modules that are tolerant to overclocking. In the Memory Configuration page, you can make further adjustments to the memory's latencies (provided this is set to Manual).
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