Full Title: The Processor Performance State Is Not Restored to the Maximum State If the CPU Runs at 100 Percent The information in this article applies to: Microsoft Windows XP Home Edition Microsoft Windows XP Professional Microsoft Windows XP Home Edition SP1 Microsoft Windows XP Professional SP1 Symptoms: The processor performance state may not be restored to the maximum state if the CPU runs at 100 percent. This problem occurs if the computer is 100 percent busy when the power policy changes. Cause: This problem may occur if the power policy changes because of an AC/DC transition while the computer is using the "Max Battery" power scheme. When the computer is running at 100 percent CPU usage, the computer never enters the idle loop in which the speed of the CPU is dynamically adjusted based on demand and current policy values. The fix is to set the timer so that Windows changes the speed of the CPU when the timer expires. A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows XP service pack that contains this fix. Changes: Q330512 adds Intel Centrino - Pentium M support to Windows XP. This is also available via a separate hotfix. The following chart lists the device driver differences in Windows XP SP1 and after the update. As you can see especially some core files are dated later than the according versions in 330512 which can be explained by updates that were released and installed after 330512. XP SP1 IncludesQ330512 Includes 5.1.2600.1106 Amdk6.sys x86 5.1.2600.1106 Amdk7.sys x86 5.1.2600.1106 Crusoe.sys x86 Unavailable Gv3.sys x86 5.1.2600.1106 Ntkrnlmp.exe x86 5.1.2600.1159 Ntkrnlpa.exe x86 5.1.2600.1106 Ntkrpamp.exe x86 5.1.2600.1159 Ntoskrnl.exe x86 5.1.2600.1106 P3.sys x86 5.1.2600.1106 Processr.sys x865.1.2600.1142 Amdk6.sys x86 5.1.2600.1142 Amdk7.sys x86 5.1.2600.1142 Crusoe.sys x86 5.1.2600.1143 Gv3.sys x86 5.1.2600.1149 Ntkrnlmp.exe x86 5.1.2600.1149 Ntkrnlpa.exe x86 5.1.2600.1149 Ntkrpamp.exe x86 5.1.2600.1149 Ntoskrnl.exe x86 5.1.2600.1145 P3.sys x86 5.1.2600.1142 Processr.sys x86 Download and install at your own risk