The main feature hyped by MSI for the P6N Diamond is the onboard X-Fi sound chip. However, the board comes with a few surprises that are not found on any of the current nForce 680i SLI boards available today.
First, let's cover some of the basics. When NVIDIA launched the nForce 680i SLI, the chipset became the first to officially support a 1333MHz FSB, which means that the P6N Diamond is still very much current and able to support the newest 1333MHz bus processors from Intel such as the Core 2 Duo E6850 and the Core 2 Extreme QX6850. MSI has yet to disclose compatibility results for 45nm Yorkfield or Wolfdale processors, but these should also be just a BIOS update away. The nForce 680i SLI may not support DDR3 memory too, but its advanced memory controller supports DDR2 up to 1200MHz as well as featuring NVIDIA's SLI Memory feature for Enhanced Performance Profile (EPP) memory modules. This should keep the P6N Diamond in contention till your next upgrade.
Now, one of the major features of the nForce 680i SLI has been triple PCIe x16 slot support, but for the P6N Diamond, MSI takes advantage of the flexibility of NVIDIA's chipset design. If you look at the board properly, you will notice that it actually has four PCIe x16 slots instead of three, making it one of the rare few boards that can support quad SLI (the first board to feature four PCIe x16 slots was the Gigabyte GA-8N-SLI Quad Royal, but quad SLI support was not yet implemented in NVIDIA drivers then).
By default, the four slots work in this mode: x16, Nil, x16, x8. This is the normal three-slot configuration and the middle yellow slot is actually deactivated. However, in a four GPU configuration, the slots will take on an x8, x8, x16, x8 mode respectively. Taking apart the chipset cooler, the board is using an nForce 680i SLI SPP combined with a proper nForce 570 SLI (AMD variant) as the MCP to make the board work in dual SLI configurations. Some of you might not realize but this is the standard chipset configuration used to derive a nForce 680i motherboard.
Traditionally most other nForce 680i motherboards fix their PCIe lane configuration as in the primary PCIe x16 slot is obtained from the SPP, while the secondary PCIe x16 slot and the PCIe x8 slots are obtained from the MCP chip. So how did MSI manage their unique quad GPU slot configuration? If you dig the specs of the NVIDIA nForce 600 series chipset deep enough, you would find that the SPP used on the nForce 680i SLI is identical to that on the nForce 650i SLI -both use the same C55 chip. Since the nForce 650i SLI offers the end user to have single PCIe x16 lane or dual PCIe x8 lanes, this was MSI's key to enable the same on their P6N Diamond. And thus their quad GPU support.
Back to audio, MSI hopes to reach out to the gamers hungering for proper onboard solution that can fully support gaming audio features like EAX and other proprietary Creative technologies. Creative's ongoing claim for the X-Fi has also been higher fps in games through more powerful audio processing. Now before the celebration begins, we have to point out that the Sound Blaster X-Fi on board the P6N Diamond is a variation of the X-Fi Xtreme Audio, the low end part in the X-Fi lineup with a 108dB SNR. Compared with most HD Audio solutions today, the X-Fi Xtreme Audio is only slightly better technically. The anchor which it rests on is its better audio performance and proper gaming support. While users of Windows XP do not have anything to worry about, Vista users are at a disadvantage. This is because Alchemy, Creative's audio wrapper project that enables DirectSound3D effects for games in Vista currently does not support the X-Fi Xtreme Audio. Thus, if you're a Vista user, having the X-Fi onboard the P6N Diamond actually offers no advantage over regular HD Audio at present until Alchemy support is finally added.
The last major feature of the P6N Diamond is the presence of a Silicon Image SiI4723 SteelVine RAID processor. The only other board we've reviewed to feature this was the ASUS P5W DH Deluxe. The SiI4723 is a 1-port to 2-port SATA 3.0Gbps chipset that supports true hardware RAID 0 and RAID 1 (no messy drivers or configuration required!). While some may complain the limited RAID support, one must remember that this is just a consumer motherboard, and manufacturers probably believe that regular users would not have need for extreme RAID setups. At least the native SATA controller on the motherboard's chipset does allow up to RAID 5.
The P6N Diamond employs a simple heat-pipe cooler for the chipset with a small footprint. This allows the board to accommodate all its expansion slots and still not look too cluttered. To compensate for reduced cooling capabilities, a fan was stuck onto the Northbridge block. While this raises up the noise level, users who purchase this board will most probably be hard core enthusiasts with plenty of other high-end components that require cooling as well so an extra hum here shouldn't be noticeable. If you need your quiet, the board works just fine without the fan, though we wouldn't recommend overclocking then.
Overall, MSI did a very good job designing the P6N Diamond. Most of the connectors are low profile and out of the way. We didn't have any problem with installation or mounting. For such a feature-rich board, its layout has been methodically thought out.