Overclocking in concert with Cool'n'Quiet
Once the snags with the DFI board and the storage drivers were finally resolved, I was able to install the rest of the device drivers and begin overclocking and tweaking. However, the mission that I'd laid out for myself contained a couple of things that generally work at cross-purposes with one another. AMD's Cool'n'Quiet technology dynamically scales back the CPU's clock speed and voltage whenever processor utilization is low. That's a great thing to have if you're looking to build a nice, quiet system, but it's the polar opposite of overclocking, which generally involves locking the CPU clock speed and voltage at higher-than-stock settings. On most Athlon 64 motherboards, you're forced to choose between Cool'n'Quiet and overclocking, especially if you're looking to overclock the CPU far enough that it would need extra voltage.

Fortunately, DFI's LANParty NF4 boards have a way around this problem in their newer BIOSes, and it's very, very slick. You can specify the amount that you want to overvolt the processor as a percentage, and the motherboard will supply that much extra voltage consistently as Cool'n'Quiet slides the CPU voltage up and down through its range of possible values.

DFI's BIOS allows one to specify a percentage above
stock CPU voltage for Cool'n'Quiet operation

In order to get my Athlon 64 X2 3800+ running stable at 2.4GHz, I knew that I needed to give the CPU some extra juice, so I set the BIOS to supply 110% of the voltage that it would at stock—in other words, a 10% overvolt. Configured this way on a 240MHz HyperTransport link, the X2 3800+ runs nice and stable at idle and under extreme loads, with a peak clock speed of 2.4GHz. Here are some CPU-Z shots from the box at idle and under load, so you can see how the CPU clock speed and voltage varies.

At idle, the CPU runs at 1.2GHz with lower voltage

Under load, the voltage and clock speed scale up beyond the CPU's defaults

Fancy, huh? I could probably back off to the BIOS's next lowest voltage option, 104%, but I haven't tested that yet.

In my case, I wasn't interested in overclocking the memory, but the DFI BIOS does provide options on that front. As you probably know, newer Athlon 64s can be set at a lower multiplier, so that it's possible to run a CPU at a relatively conservative speed on a wildly overclocked HyperTransport link (whose clock also governs memory speeds). For instance, I might choose to run my HT link at 280MHz and lock my X2 3800+ at a multiplier of 8, yielding a 2.24GHz CPU clock and 560MHz memory. Such spectacular feats of memory overclocking haven't, in the past, been possible in conjunction with Cool'n'Quiet, because C'n'Q will ramp the processor up to its highest possible multiplier as soon as the system's under load. On my X2 3800+, that would result in a 2.8GHz clock speed and a very nasty crash. The DFI BIOS, however, allows the user to specify a maximum CPU multiplier value for Cool'n'Quiet, neatly solving that problem.

The end result is that I have a system that runs slower than stock when I don't need any extra performance, with lower voltage and less power consumption; it then runs faster than stock, with higher clock speeds and a little extra voltage, when I need it most. These options may be available in the BIOSes of other Athlon 64 boards, but I haven't seen them. I think they should become a practical requirement for an enthusiast motherboard's BIOS.