This article was previously published under Q316965
The System tool in Control Panel may not report your computer's processor speed correctly. The difference between the reported speed and the actual speed may be small or large.
Small differences between the reported speed and the actual speed may be caused by the mathematical formula that Windows XP uses to calculate the processor speed.
Larger differences may be caused by Windows XP reporting the current speed of the processor rather than the processor's fastest possible speed.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
You may want to contact your computer manufacturer to verify the fastest possible speed of your computer's processor.
Windows XP differentiates between a processor's current speed and its maximum speed. In computers that use processor-throttling technology (such as the Intel SpeedStep or AMD PowerNow! technology), the processor's current speed may be different from its maximum speed. The processor's speed may be reduced to conserve battery life. If Windows XP queries the processor to determine its maximum speed while the processor is in a throttled (or reduced-speed) state, Windows XP reports a processor speed that is lower than the processor's actual maximum speed.
To Check the Speed Settings
To Check the Current Speed Setting
Click Start, click Control Panel, and then click Performance and Maintenance.
Click See basic information about your computer. The processor speed (in megahertz [MHz] or gigahertz [GHz]) appears under Computer on the General tab.
Note that some manufacturers place the processor speed in the CPU ID string that is displayed in this dialog box. If two speeds are listed, the second speed is the current speed setting.
To Check the Maximum Speed Setting
Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Information. The maximum speed of the processor appears (listed in MHz) next to Processor in the right pane of the System Information window. The System Information tool always reports the maximum speed of the processor.
If you click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Information, the correct processor speed is shown (for example, a displayed 797-MHz speed equals 800 MHz). After you start the System Information tool, the System tool in Control Panel displays the correct speed. However, when you first start your computer, the incorrect speed may be listed in the System tool in Control Panel.
Note If you use Windows Vista, you can visit the following Microsoft Web page for help with power consumption and battery life problems: