Does disabling a core in a multi-core conserve power/heat?

[kevinfelker42]

I was reading you can disable a CPU core doing this:

You need to right click on "My Computer" -> Properties -> Advanced -> Startup & Recovery;
There, you will find a button named "edit" - by pressing it you can edit the Windows Boot.ini file manually.
at the end of the line add the following code:
/numproc=1
save the Boot.ini file and reboot
Your Windows XP Install will now only use one Processor Core.

If you did so, would this reduce heat and power consumption?

I don't have a power meter (kill-a-watt on its way), so I can't test this.

I don't know if doing this is only a software disable, or an actual hardware level change.

Can anyone give more detail?

[aaa]

Doing it in the BIOS does save power, about 2w for an Intel. I doubt disabling it in Windows would make as big of a difference.

[bob8701]

it is odd to see people try to disable the core, most people have problem to enable. Intel cores are glue together and amd's are separate, so I guess by doing so, amd should save more power than intel.