seebs
10-28-2007, 01:08 PM
Well, really, just undervolting.
I have a machine built around an AMD Athlon X2 6400+. Rated thermal dissipation? 125W.
The thing is, I don't like loud. So I have a big copper heatsink (Zalman 9500) and a nice case and so on. But under peak load, it still spins the fan up enough to annoy me.
Enter undervoltage.
When overclockers run a system above its rated speed, part of how they make it work is increasing the voltage. However, you don't always need to increase the voltage much to increase speed...
And that corresponds to a similar ability for the machine to run at its regular speed at a lower voltage. Since a rise in voltage produces a corresponding rise in amperage, and wattage is V*A, this turns out to mean that voltage modifiers are quadratic; double the voltage, quadruple the power.
So I tried 1.3V (down from the rated 1.4V), and the system seemed mostly normal, but burnK7 (a CPU heat generator, basically) churned up occasional errors. I'm trying 1.325 now. If I can get that to work, I'll be saving a tad over 10% of the CPU's total heat dissipation, which is enough to make a noticable difference.
I have a machine built around an AMD Athlon X2 6400+. Rated thermal dissipation? 125W.
The thing is, I don't like loud. So I have a big copper heatsink (Zalman 9500) and a nice case and so on. But under peak load, it still spins the fan up enough to annoy me.
Enter undervoltage.
When overclockers run a system above its rated speed, part of how they make it work is increasing the voltage. However, you don't always need to increase the voltage much to increase speed...
And that corresponds to a similar ability for the machine to run at its regular speed at a lower voltage. Since a rise in voltage produces a corresponding rise in amperage, and wattage is V*A, this turns out to mean that voltage modifiers are quadratic; double the voltage, quadruple the power.
So I tried 1.3V (down from the rated 1.4V), and the system seemed mostly normal, but burnK7 (a CPU heat generator, basically) churned up occasional errors. I'm trying 1.325 now. If I can get that to work, I'll be saving a tad over 10% of the CPU's total heat dissipation, which is enough to make a noticable difference.