Disabling Cores = Longer Battery Life?

Hi all, I'm new to the forums, but I have been following reviews on this site for quite a while.

So, my dilemma is that I want a quad core Sandy Bridge based laptop for university, but at the same time I want something like at least 6 ~ 8 hours of battery life. So I thought of a compromise last night - what if I could disable 2 cores in the CPU when running on battery and re-enable them when on AC? In theory, it should cut CPU power consumption by a good amount if the OS doesn't schedule anything onto them and they are asleep, right? Well, I came across something on the internet earlier today that allows one to do exactly that - use only as many cores as you want.

Instructions:
1. Press start, type MSCONFIG, press enter
2. Go under the boot tab, click Advanced Options
3. Set the number of processors

Image:
http://img34.imageshack.us/i/boot001.png

So, can someone with a quad core laptop test this out, and post your battery life with all 4 cores, and with disabling 2 cores, please?

Thank you in advance.

 

I'm sorry man, This DOES NOT affect your PC, when done booting. It allows you to choose how many processors to use, and memory when windows is starting. But not when windows is running normally
1 I am very sure u can still under clock it to reduce power consumption
2 Most power consuming component is display, so try reducing brightness
GOOD LUCK!

 

Hmm...
Well, on my desktop, Windows only recognizes 1 core in task manager instead of 2 when I set the core count to 1 instead of 2, and there was definitely a noticeable performance decrease.

I know that the most power consuming component is the display, and from what I've seen so far after playing around on several laptops, I usually use the display at 40% ~ 60% brightness.

I do not currently own a laptop, though I do have a netbook (Compaq Mini 110-1100CA).

 

...oh God, not another of these threads...
That option is meant ONLY for troubleshooting issues at boot, nothing more.

And more cores working on one task is more power efficient than fewer cores working on full load.

 

Seconded. The CPU has various power states, and the longer it's in the higher power states, the more battery it uses. It's not linear, either... the highest power states use a lot more power than the lower power states). It's actually more efficient to run two cores at low load than a single core at a higher load due to the power usage. It also allows high-load tasks to finish faster so the CPU can get back to low-load state.

The ONLY place it might make some difference is if your CPU is 100% utilized on battery whether multi or single core, but in that case you should be plugged into power anyway.

 

if you have an I7 especialy SNB it could help cause the un used cores will power gates them selfs out of the circuit(irronicaly sandy bridge's power saving tech is adrealy great enough so doing so could change very little) but for C2Q and Arrandale it's useless since core dannot dwelve in sleep mode if ther other cores are in use

 

and developers to test easily for different hw scenarios.