Undervolting a laptop

Undervolting: Setting the voltage for the highest frequency

Now that we’ve set the lowest clock frequency, we can’t of course be satisfied with the CPU running at 50% of the original clock. Let’s go on to the next step. Setting the VID of the highest clock frequency.

We add another PST. This PST should have the highest FID (8x) and because I checked the “General” tab before is started the undervolting, I know that my standard voltage is 1.450V. We should do perform the same procedure like in the previous chapter, but we will use a different FID and VID. We set the VID to a value less than the standard value, and the new voltage is now 1.425V. Before clicking “OK”, we set the profile to maximal. Because we now have two values in the list the CPU will only use the highest FID when the CPU is under load. When we set the profile to Maximal it ensures us that will run at 8x. (If we choose the profile Minimal it will in the same way run at 4x). We click on “Apply” and check the “General” tab to confirm that everything is correct.
Let’s run Prime 95 to stress the CPU.
Like in the previous stress-test, everything will run just fine and we can continue to lower the voltage until we reach our “crash-voltage”.

In my case the actual “crash-voltage” was 1.125V. I could run Prime 95 for an hour without problems at 1.150V but I didn’t think it was stable enough and therefore I increased the voltage an additional step to 1.175V. Now you see the difference between the voltages. The original was 1.450V but I could lower it all the way down to 1.175V, a reduction of 19%. This gives me advantages that I will discuss further.

The undervolting is almost complete and now we should configure the auto start settings…