CPU not running at full speed in Windows 11/10: how to fix it

Applies to: Windows 11 and Windows 10, Intel and AMD processors, desktops and laptops. Menu names below are from Windows 11; Windows 10 differences are noted.

1. Check that it’s really stuck

1. Press Ctrl + Shift + Esc to open Task Manager and go to Performance > CPU.
2. Compare Speed (the current clock) with Base speed. Below base at idle is expected.
3. Now give the processor real work: open several heavy apps, start a large file compression or a game, and watch Speed for a minute.

If Speed climbs to around base speed or above under load, the CPU is fine and the slowness is elsewhere; 100% disk usage is a common culprit. If it stays at a fixed low value, often 0.4 to 0.9 GHz, while Utilization is high, something is capping it. Work through the steps below. If utilization itself is stuck high, find the process first; svchost.exe (netsvcs) high CPU covers one frequent case.

2. Set the power mode

Windows lets you trade speed for battery life. Open Start > Settings > System > Power & battery and set Power mode to Best performance. On laptops there are separate settings for Plugged in and On battery; set the one you’re using.

If the Power mode option is greyed out, Microsoft says a custom power plan may be active: open Control Panel > System and Security > Power Options and select Balanced, then change the mode again. On Windows 10, click the battery icon on the taskbar and move the slider towards best performance (not every PC has the slider).

3. Check the maximum processor state

Every power plan has a cap called Maximum processor state, a percentage of the processor’s full performance. A plan set below 100%, by a tuning app, a vendor utility or an old tweak, holds the CPU down no matter which power mode you pick.

1. Open Control Panel > Power Options, click Change plan settings next to the active plan, then Change advanced power settings.
2. Expand Processor power management > Maximum processor state.
3. Set both On battery and Plugged in to 100% and click OK.

You can do the same from an elevated Command Prompt. The first command shows the current processor settings for the active plan; the next three set the cap to 100% on mains power and battery and re-apply the plan:

powercfg /query SCHEME_CURRENT SUB_PROCESSOR
powercfg /setacvalueindex SCHEME_CURRENT SUB_PROCESSOR PROCTHROTTLEMAX 100
powercfg /setdcvalueindex SCHEME_CURRENT SUB_PROCESSOR PROCTHROTTLEMAX 100
powercfg /setactive SCHEME_CURRENT

PROCTHROTTLEMAX is the alias Microsoft documents for this setting, and powercfg /aliases lists the others. Leave Minimum processor state low; raising it only stops the CPU from saving power at idle and doesn’t lift a cap.

Some guides suggest disabling the intelppm driver or renaming its file. Don’t: it is part of Windows’ processor power management, and removing it can cause other problems while not fixing a hardware cap.

4. Laptops: charger and battery

When a laptop can’t draw enough power, its firmware throttles the processor hard, which is the classic stuck at 0.4 GHz symptom. Common triggers reported by owners and repair forums:

• A charger with lower wattage than the original, a third-party charger the laptop doesn’t recognise, or a damaged cable. Many laptops show a warning at startup when they can’t identify the adapter.
• A worn-out or failed battery, which some models rely on for extra power under load.
• A USB-C charger or dock that delivers less power than the laptop needs.

Test with the original charger plugged directly into the wall. If speed returns, replace the adapter or battery; the laptop maker’s diagnostics (built into most models’ boot menus) can check both.

5. Rule out overheating

Processors slow themselves down to protect against heat. Dust in the vents, a failing fan or dried thermal paste can make that happen at normal loads. Signs are a fan running loudly, a hot base, and speed that starts high and then drops after a minute of work. Clean the vents with compressed air with the PC off, keep laptops on a hard surface, and use the manufacturer’s diagnostics to test the fan. Replacing thermal paste is a repair-shop job on most laptops.

6. Update the BIOS and check CPU settings

Firmware sets the processor’s power limits, and a bug there can cap the clock. Dell, for example, documents an XPS model stuck at 0.8 to 0.9 GHz when Intel SpeedStep and Turbo Boost had been switched off, fixed by updating the BIOS and re-enabling both. Install the latest BIOS or UEFI firmware from your PC or motherboard maker, then check in the firmware setup that options such as SpeedStep (Intel), Cool’n’Quiet or Precision Boost (AMD) and Turbo Boost are enabled or on their defaults. Use the maker’s own instructions for the update; never interrupt it.

If nothing here helps and the speed is low on mains power with the original charger, a cool machine and current firmware, contact the manufacturer: a failing sensor or power circuit can trigger the same throttling.

Related guides

• 100% disk usage on Windows 11: how to find the cause and fix it
• svchost.exe (netsvcs) high CPU or memory: how to fix it
• Windows 10 slow boot: how to fix it
• How to stop CHKDSK at startup in Windows 11 and 10

Official sources:

• Microsoft Support: Change the power mode for your Windows PC
• Microsoft Learn: Maximum processor state (PROCTHROTTLEMAX)
• Dell: XPS 9315 processor speed stuck between 0.8 and 0.9 GHz