How to test whether heat slows your laptop

Your laptop feels fast when you first turn it on, then slows down after a game, video call, or other demanding task. Heat can make a processor reduce its speed, but background apps and power settings can cause similar symptoms.

Compare a processor test before and after a short heat test to see whether performance drops under load. This can show a repeatable slowdown, but it does not measure the laptop's internal temperature or prove which part is responsible.

Test whether heat slows the laptop

1. Put the laptop on a hard, flat surface with its air vents clear. Close games, video calls, and other demanding apps. If it is already unusually hot, let it cool before testing.
2. Open the Processor Test and run it once. Note the single-core and all-core results, including the score out of 100 if shown. Keep the laptop plugged in or unplugged for every run, and use the same power mode each time.
3. Open the Overheating Test and run its full-load test for a few minutes. Stay with the laptop, keep the vents uncovered, and stop if it shuts down, displays a warning, or becomes uncomfortably hot.
4. Run the Processor Test again as soon as the load test ends. Compare the results with your first run. If the results differ, let the laptop cool and repeat the comparison once under the same conditions.

Use the same browser and avoid changing power settings between runs. A benchmark score can vary slightly from one run to another, so a small difference by itself does not show that heat is the cause.

What the result means

The second processor score is clearly lower

A repeatable drop after the full-load test suggests the laptop is reducing performance under sustained demand. Heat is one possible reason, especially if the fan gets louder or the case becomes warm. The test cannot identify a faulty fan, blocked vent, or exact temperature, so check the cooling conditions before deciding it needs repair.

The scores are close

The test did not show a clear slowdown in this short run. That does not rule out a problem that takes longer to appear or happens only in a particular app. If you notice the lag during video calls, large downloads, or a game, check whether other programs are using the processor at the same time.

The second score is higher

Small increases can happen because the first run was affected by background work or normal variation. Restart the laptop, wait for it to settle, and compare again. A higher score does not mean that running the heat test improved the hardware.

The laptop becomes very hot, shuts down, or warns you

Stop the test. A shutdown or temperature warning is a stronger reason to check cooling than a minor benchmark change. Do not keep repeating a full-load test to try to force a result.

How to reduce heat-related slowdowns

1. Clear the air vents. Use the laptop on a desk or table, not a bed, pillow, or blanket. Soft surfaces can cover the intake or exhaust vents and trap heat.
2. Check for a busy app. On Windows 11, press Ctrl + Shift + Esc to open Task Manager, then check which apps use the most CPU. On macOS, open Activity Monitor from Applications, then check the CPU tab. Close an app only if you recognize it and do not need it.
3. Check the power mode. On Windows 11, open Settings › System › Power & battery › Power mode. On macOS, open System Settings › Battery and check whether Low Power Mode is on. Power-saving modes can lower performance, so keep the same mode for your tests and choose a normal setting for everyday use.
4. Restart and retest. A restart can clear a stuck app or background task. After the laptop has cooled, repeat the processor comparison without changing the charger, power mode, or test conditions.
5. Keep the cooling area clean. If dust is visible around the vents, follow the laptop maker's cleaning instructions. Do not push objects into the vents or use a vacuum nozzle against them.
6. Install system updates when convenient. Updates can fix power or fan-control problems, but avoid starting an update during a comparison test. Restart afterward and check whether the slowdown returns.

When the laptop may need repair

If the laptop repeatedly slows down under load on a hard, clear surface, and the fan does not seem to move air or makes a new grinding noise, its cooling system may need attention. Frequent temperature warnings or shutdowns also deserve a check. Contact the manufacturer or a repair shop, especially if the laptop is under warranty. A browser test cannot confirm whether a fan, heat pipe, or other internal part has failed.

What this test cannot measure

The Overheating Test looks for performance slowdowns under full load. It does not read the laptop's temperature sensors, and a browser benchmark is not a substitute for a service diagnostic. For another way to look for processor slowdowns without temperature readings, see How to detect CPU slowdown without temperature readings.