Stop Processor Throtteling / Whining

Modern computers (mostly laptops and nettops) are build with processors that are capable of a variety of features for saving power. These features a commonly known as Throtteling and Idle-states and they ensure that processors are not waisting energy on doing nothing - wich is not that bad at all since we save power and thereby expand the battery-life.

BUT! These features often generate a high pitch noise which some people cannot hear whilst other people can be quite annoyed by them. The noises sounds almost like a doped mosquito buzzing next to your ear - and who likes that? In Windows Vista and Windows 7 there are no apparent options for controlling these throtteling features - but you can actually quite easy control them anyway. This guide demonstrates how easy it is to control throtteling and power-states in Windows Vista and Windows 7.

If you enter your Control Panel and open the Power Options applet you will be able to select and manage your power plans. If you then click "Change Plan Settings" you will be able to change some basic settings for the selected plan. However, if you click "Change advanced power settings" you will get a lot of extra features to change. The most interesting setting for us is the "Processor power management".

By default you are only able to change the minimum and maximum processor state defined as a percentage of the processors full power. Changing these values does nothing with the squeal since the squeal is related to the different C-states (or power states) of the processor. C-states are defined as follows (simplified):

C1 Processor is working
C2 Processor is waiting to work (full clock speed is maintained)
C3 Processor is waiting to work (clock speed is downed; it will take a few milliseconds to clock-up again)
C4 Processor is completely shut down (clock speed downed; cache ditched; it will take longer than C3 to wake up).

It is in fact these states that are responsible for generating that pesky high pitch noise and it is most likely to appear when the system is switching the processor between the states. It is actually not the processor itself that generates the noise but rater some components of the motherboard.

Here comes the honey: If you start the registry editor (by typing "regedit" into your search field in the start menu and pressing [enter]), you will be able to directly manipulate all the settings in your Windows system. This can of cause end up with a hanging system so please be carefull when doing this. Now, open the following branch in the registry:

All sub-keys to the key above has something to do with the processors power manegement. It is very different what types of sub-keys you have and it depends on the processor, the motherboard (BIOS) and the version og Windows you are using. This is why I cannot direct you to a specific sub-key in order to complete this guide. What you need to do now is to select each sub-key one after another and look at the values attached to it in the right side of the registry editor. You will need to find a key, that has a value like this: On my computer the sub-key containing this value is called "3b04d4fd-1cc7-4f23-ab1c-d1337819c4bb". The key has a value named "Attribute" which by default is set to true (or the numerical value 1 / one). If you double-click this value and change it to "0" (numeric value of zero) instead (save by clicking "OK") you will be in for a surprise!

Now, open your Control Panel and enter Power Options again. Open "Advanced power settings" for the desired plan and go to "Processor power manegemnt". Whooha! Now you can actually disable throtteling of your processor! As soon as you chose to disable throtteling and click OK - the high pitch noise will dissapear immediately! SWEET!

However, this tweak comes at a price.. Since the processor is no longer throtteling down and always keeps its cache valid the temperature rises and this will most likely cause your fan to spin some more in order to keep the computer cool. Also, your battery-life will be cut by a bit - but now you know how to enable or disable processor throtteling in Vista & Win 7 :-)