A Windows computer may reduce its processor speed to save power, control temperature or stay within a hardware limit. If reduced performance is unexpected, checking the power plan can help identify a software limit before investigating cooling or the host server.
Check the cause
Compare performance during a representative workload, rather than while the computer is idle. Task Manager shows utilisation and speed, but does not identify every reason for a reduced clock speed.
On a virtual server, ask the provider to check host resource limits if performance remains low. Changing a Windows power plan cannot remove a limit imposed by the host.
Do not disable thermal protection. A processor reducing its speed because it is overheating needs its cooling problem resolved.
Review the Windows power plan
- Press Windows + R, enter
powercfg.cpland press Enter. - Beside the active plan, select Change plan settings, then Change advanced power settings.
- If available, expand Processor power management > Maximum processor state.
- Record the current setting. For a computer connected to mains power that should allow full processor performance, set Plugged in to 100%.
- Select Apply, then OK, and repeat the same workload.
The available settings depend on the device and its management policy. A 100% maximum permits full performance; it does not force a constant clock speed or override temperature limits. Restore the previous setting if the change causes unwanted heat, noise or power use.
Investigate continued poor performance
Check cooling and hardware diagnostics using the computer manufacturer’s instructions. For a managed or virtual server, provide the support team with the workload, time of the problem and observed utilisation. Process priority changes do not directly change the processor’s clock speed.