Corporal wrote:
1. Probably not
2. You won't notice any difference, because you can't save anything with dropping the frequency, you will have to undervolt as well. Major part of the energy consumtion is due to the GPU being on at all times. Undervolting the CPU will probably affect your stability and won't get you any significant gains.

Hi

Thanks for replying. Good point about the GPU burning most power.
I guess we would need some way to turn off the NVIDIA GPU (965m) and use the CPU Integrated Graphics to save power (switchable graphics).
I have also heard of Nvidia Optimus Technology which I don't think is available on the 965M in the G751JL. Not sure exactly what it does though.

I thought that dropping the multipliers on the CPU would drop the frequency and therefore drop the power consumption.
Since Power = C * (V)^2 *f , (C= capacitance = "fixed load", V= voltage, f = frequency), dropping either f or V should help with battery life.

Undervolting would have much more (squared) effect per unit voltage change but I was just thinking since the drop from say x32 to x8 multiplier is quite a drop in frequency... it should be worth something. As you say, undervolting can cause stability issues, but I cannot really see how dropping the CPU frequency should affect the stability of the CPU itself. It should just make the CPU run slower.

Do you think that dropping the CPU frequency using these multipliers would cause system stability issues though? For example maybe the CPU could end up unable to communicate correctly with the surrounding chipset?

Thanks again for your input.

colesdav wrote:
Do you think that dropping the CPU frequency using these multipliers would cause system stability issues though?

Dropping voltage saves battery but affects stability.
Dropping frequency won't affect stability, but doesn't save battery either. It may actually increase your battery consumption.
Lets assume an operation you need to perform takes 5 minutes @ 3500 MHz. It would take about 22 minutes for the same operation to be performed at 800 MHz.
Even if your CPU is more efficient at 800 MHz, there are other components like GPU and LCD which will drain your battery for 17 additional minutes. That way, anything you gain by making your CPU slower is offset by other components.

virusce0707 wrote:
if you want to save power go in control panel and put max cpu performance on something else than 100% on battery I have about 30-40 % + time

The "max CPU" setting doesn't work in windows, and if it did, it would increase battery consumption, see post above. The "min CPU" setting works though.