SpeedswitchXP

SpeedswitchXP is a small applet that sits in the system tray and allows dynamic switching of the frequencies of mobile Intel and mobile AMD CPUs under Windows XP.

During the development of Windows XP, Microsoft decided to integrate dynamic frequency switching into the operating system itself. On a default Windows XP installation, the power schemes in the power settings of the system panel control the frequencies of the processor. On Windows 2000 and previous operating systems, it was possible to manually control the CPU frequencies with a SpeedStep applet provided by Intel, but this is not possible anymore under Windows XP. It is not very good documented what the different Windows XP power schemes do and it is impossible to fully adjust the schemes as the important settings are not accessible through the control panel.
SpeedswitchXP tries to fill this gap in that it provides access to ALL power scheme settings. This small applet is similar in functionality to the native Intel SpeedStep applet for Windows 9x/ME and Windows 2000 but with a few more options.

Basically all it does is creating a power scheme under the power settings in the system panel and making this the default power scheme for Windows XP. When this is done, you can control all settings of this new scheme through the applet.

Since this program is using Windows XP's internal processor performance control functions, it should work on all notebooks that feature dynamic speed switching. So far, it has been successfully tested on notebooks with the following mobile CPUs: