BIOS and Overclocking
The K8N Diamond Plus uses an AMI BIOS, which has been organized in such a manner that all of the necessary options are laid out in a clean and easy to navigate system. The BIOS is incredibly tweakable, as expected from a high-end enthusiast board of this nature. Even so, with all the options available, we're happy that MSI was able to keep everything in such an organized manner.
Some of the more interesting BIOS options lay in the "PC Health Status" and "Cell Menu" sections. PC Health Status includes all of the motherboard's thermal sensors and the smart fan speed controls. From here, we can see that the nForce4 Northbridge fan runs at a default RPM of ~5,500 RPM. However, unlike most motherboards, the fan speed of the chipset fan can be controlled in the BIOS, along with the CPU fan, using MSI's smart fan technologies. In particular, we were fond of the "Thermal Cruise" mode, which will gradually slowdown or spin-up fans depending on the thermal sensor levels. In a cool environment, we were able to see our CPU fan spin down from its default speed of 4000 RPM to a low point of 900 RPM, whereas our Northbridge fan was able to spin down from 5500 RPM to roughly 2000 RPM. The fan speed changes are so gradual that it's very easy to tune out the noise level changes. At its lowest level, the Northbridge fan is nearly inaudible, while it's slightly noticeable when running at full speed. If you use this board, we would certainly recommend enabling Thermal Cruise mode, as it does make the board much more enjoyable to be around.
The Cell Menu contains all the fun stuff in regards to overclocking. The BIOS lets the user set the front side bus speed from 200 MHz to 450 MHz in 1 MHz increments, whereas the CPU voltage levels can be set up to 1.475V. The motherboard supports DDR memory voltage alteration from 2.65V to 3.2V (and up to 4.10V in boost mode), but does not have the necessary divisors for DDR-433/466/500 memory, like most new enthusiast platforms do. One can also adjust PCI Express clock speeds/voltages and HyperTransport link speeds/voltages, although in most scenarios these should be left to their defaults. The motherboard also supports dynamic overclocking, from 1-15%, and also can auto-overclock your GeForce GPU/memory clock speeds if enabled in the BIOS. This didn't work too well for us, as even setting the dynamic overclocking mode to 5%, our system became unstable and programs started crashing. Manual overclocking is certainly the way to go if you want to get the most out of your components on this motherboard.
Temperatures can be monitored within the BIOs or through one of two Windows interfaces. The MSI board not only supports nVidia's (excellent) nTune monitoring and tweaking software suite, but MSI bundles their own CoreCenter software which interfaces directly with their CoreCell chip onboard. CoreCenter is a big, rather complicated looking application which has a busy interface and is somewhat difficult to use. However, as a thermal monitoring suite, it does work, although nTune is far cleaner. CoreCenter also allows for on-the-fly clock speed and voltage alteration, which is good for minor tweaks, but for serious overclocking we would recommend doing so from the relative safety of the system BIOS.