BIOS and tweaking software
Mid-range boards like the K9N SLI Platinum are prime candidates for overclocking, and MSI has equipped the BIOS with all the bells and whistles you'll need to push an Athlon 64 beyond its stock speed.

HyperTransport clock speeds are available up to a whopping 425MHz, and CPU voltages go up to 1.7V. There's no provision for increasing the chipset's voltage, but memory voltage options are available up to 2.45V.

If you prefer a more dumbed down approach to overclocking, the K9N SLI's BIOS also has a handful of automatic overclocking options that will increase the processor speed by between 1% and 15%. Most enthusiasts should be comfortable enough manipulating the processor multiplier, HT clock, and memory speed, though.

Speaking of memory, the K9N SLI's BIOS has all the usual timing options, including control over the DRAM command rate. Unfortunately, there's nothing MSI can do about the Athlon 64's limited memory bus divider options. The Athlon 64 calculates the memory bus speed as a factor of its core clock, and for some speed grades, it's impossible to have DDR2-800 memory running at exactly 800MHz. For example, the closest the Athlon 64 X2 5000+ can bring its memory bus to 800MHz is 742MHz.

At least MSI does a good job with the K9N SLI's processor fan speed control. Temperature-based automatic fan speed control is supported for three- and four-pin fans, and users can choose between four target CPU temperatures. Ideally, we'd like to be able to define arbitrary target temperatures and fan voltages for each onboard fan header, but few BIOSes go that far.

For those who prefer to do their BIOS tweaking from Windows, MSI supplies a version of its CoreCenter software with the board.

However, unless you crave limited functionality and an ugly, awkward interface, you shouldn't install it. Instead, skip right to Nvidia's latest nTune system utility, which sports a much better interface and a broader array of options than MSI's software.

MSI hasn't included the necessary BIOS hooks to make all of nTune's widgets work, but you still get control over loads of memory timings and the HT clock. We'd really like to see MSI update the K9N SLI's BIOS to allow nTune to manipulate system voltages, which are currently unavailable.

Fortunately, BIOS hooks aren't necessary for nTune's custom rules feature. Custom rules allow users to define and activate system settings profiles based on application activity and variables like processor temperature, so you can have separate profiles automatically launch for games, media playback, and so on.

nTune also has a monitoring app that keeps tabs on various system variables, including clock speeds, voltages, and fan activity. The monitoring app can even log variables to a file if you want it to keep an eye on things.

Overall, nTune is a much better monitoring and tweaking utility than what the vast majority of motherboard manufacturers develop in-house and bundle with their boards. Manufacturers would do well to support it fully rather than dedicating additional resources to developing proprietary apps.