High CPU usage in Windows 11

Establish the scope

Open Task Manager with Ctrl+Shift+Esc and compare CPU use while the PC is idle and during the slow task. Record the process name and whether demand subsides when a known workload finishes. A short spike is different from sustained use, and the System interrupts entry needs device evidence rather than an attempt to end it.

Apply the safer fix first

Observe for several minutes and identify the process. Let legitimate updates or security scans finish; do not end unfamiliar system services.

Investigate the cause

Repair the named app. For sustained System interrupts, disconnect peripherals one at a time and check OEM chipset and device drivers.

Protect the recovery path

Save work before closing an application; do not end unfamiliar system processes. Safely eject storage before peripheral isolation and stop for heat or power warnings.

Verification

• Repeat the original workload and check whether its response improves as the identified CPU demand changes.
• Confirm the process settles when its work finishes; low CPU with the same slowdown means another resource needs investigation.

When to stop

Do not continue with broader resets when temperature warnings, shutdowns, unknown processes, or persistent interrupts appear. Preserve the observations already collected and use the device maker, network administrator, Microsoft support, a qualified repair technician, or data-recovery help according to the evidence.

Review the safe troubleshooting workflow before any broader recovery step.