Undervolting a laptop

Undervolting: Setting the voltage for thelowest frequency

The next thing we have to do is activate the profile ”Automatic Management” on both the “AC Profile” and the “Battery Profile”. Now the program determines our settings. Most computers today use “Throttling” that allows us to set a lowest/highest clock frequency. In my case the choice is between 4x FID or 8x FID. (This varies between computers and in my case 4x equals 800 MHz and 8x equals 1600 MHz. Now we should clear the list by pressing the Delete-button. If this doesn’t work, you can edit the PST’s that already are in the list.
We begin by setting the lowest FID, if you don’t know the original voltage of your FID; you can check the “General” tab and see what your “Current VID” is.

I already know that my standard 4x VID is 1.0V and I will therefore lower it one step. In other words, to 0.975V. I click “OK” and check the list to see if everything is correct. There should only be one value in the list and in my case it should be: “State No. 0, FID 4x, VID 0.975V”. After confirming this by clicking on “Apply”, my computer should now be undervolted. We check this by looking at the first tab, “General”, under “Current VID” it should now say 0.975V. Once again I must remind you that these are my values. Your values may look different.

Hopefully your CPU is not a “Friday Afternoon Syndrome” sample, and can still read this and you’re ready to start stress-testing it using the new voltage. Let’s start our stress-test with Prime 95. We will run a quick test that lasts a few minutes to see if it works. If this works without any problems, we can try to lower the voltage a bit further, down to 0.950V. If it still works, you can lower it a bit further, and then some. I guess you understand the context now so I will fast-forward to the point where it doesn’t work anymore.
As an example: At 0.900V my computer crashed and rebooted. The computer was stable at 0.925V. After I’ve entered Windows, I have to start the program and adjust the settings again.
Because we’ve now found our “crash-voltage”, we can avoid lowering it further and can satisfy with a voltage of 0.925V. Since we’ve only performed a quick-test of the CPU at this voltage, we will now start a longer test that will take between a half-hour and an hour. That should be enough.

There, now we have set the lowest clock frequency and now we must off course set the highest.