why does bumping up the voltage help OC a cpu?

[thehammer]

running 600@900 on abit kt7, 1.65v 44C. As the title says, why does it work? I can hit 950 with 1.75v but below that, say 1.65V, the screen stays black. Bump it up, and i get a checksum error. Bump it up a little more, system posts but windows does not load. Bump up the voltage yet again, loads windows but crashes, final bump and it runs stable.

 

[Remnant2]

There's a great article on Real World Tech about how overclocking actually works.

The short version is, CMOS devices (in this case the transistors and circuits that make up your CPU) operate at different speeds under these conditions:

1) The lower the temperature, the faster they run
2) The higher the voltage, the faster they run

In overclocking, we principally work with #2, as we can't effect a large enough change in #1 to make a difference. The big heatsinks and stuff that we slap on are more designed to reduce the additional heat that higher clock speeds produce to the original spec levels, not reduce it below them.

For an example of overclocking by #1, take a look at the cyrotech systems, which use refriguration to cool the CPU to around -32 (I believe), thus allowing the CPU to run much faster.