How to monitor CPU usage in Windows using Resource Monitor

Monitoring CPU usage in Windows helps explain slowdowns, fan spikes, battery drain, and sudden UI lag by pinpointing which process is demanding processor time.

The built-in Resource Monitor provides a process-level view of CPU activity using Windows performance counters, including instantaneous CPU use, a rolling Average CPU, and related details such as Threads and service groupings. Compared to Task Manager, the CPU tab makes it easier to filter down to a single process and correlate it with services, modules, and system-level load graphs.

CPU percentages are shown as a share of total available processing across all logical processors, so a single busy thread may appear as a modest percentage on systems with many cores. Closing suspected applications normally is safer than terminating system processes, since forcing critical components to stop can cause instability or require a restart.

1. Open Task Manager using Ctrl + Shift + Esc.

   Task Manager can also open from the taskbar right-click menu.

2. Open Resource Monitor via Task Manager → Performance → Open Resource Monitor.

   Resource Monitor also opens from Run (Win + R) using resmon.

3. Select the CPU tab in Resource Monitor.
4. Sort the Processes list by clicking the Average CPU column header.

   Average CPU highlights sustained load, while CPU is more sensitive to short spikes.

5. Select the checkbox next to a high-usage process to filter the lower panes to that process.

   Filtering helps map a busy process to related services, handles, and loaded modules.

6. Review the Services section for the filtered process to identify the service consuming CPU under a shared host process.
7. Review the Threads column for the filtered process to spot unusually high thread counts.

   A rapidly growing Threads count can indicate a stuck loop, runaway worker creation, or a plugin add-on issue.

8. Observe the CPU Usage and Maximum Frequency graphs to correlate load with throttling behavior.

   Consistently low Maximum Frequency can indicate power-saving limits or thermal throttling under sustained load.

9. Close the suspected application from its window or system tray.

   Avoid terminating unknown system processes from Resource Monitor, since forcing critical components to stop can crash Windows or trigger a restart.

10. Confirm the process drops to low Average CPU or disappears from the Processes list.