Why does my laptop get slow when it gets hot?

Your laptop may feel hot, the fan may get loud, and then everything starts to lag. Apps take longer to open, video stutters, or the cursor stops responding smoothly. That can happen when the laptop reduces its speed to control heat, but background activity and power settings can cause similar symptoms.

The Overheating Test puts the processor under load for a few minutes so you can check whether performance drops as the laptop heats up. Use it only when the laptop is on a hard, flat surface and is not showing a temperature warning or shutting itself off.

Check whether heat is slowing your laptop

1. Save your work and place the laptop on a hard, flat surface. Keep the air vents clear. If it is already extremely hot, smells unusual, or has displayed a heat warning, let it cool instead of testing it.
2. Open the Overheating Test in your browser. Close demanding apps first so they do not affect the result.
3. Run the test for a few minutes and notice whether the laptop becomes less responsive as it warms up. Stop if it becomes unusually hot, shuts down, or shows a warning.
4. After the test, let the laptop cool and try the task that was making it slow. Compare how it behaves when cool with how it behaves after longer use.

A browser test cannot measure every part of a laptop or reproduce every game and app. Use it as one clue, alongside the timing of the slowdown, fan noise, and how hot the laptop feels.

What the result means

It slows down as the test continues

Heat may be reducing the laptop's performance. Processors can lower their speed when they get too hot. This is called thermal throttling. It helps protect the hardware, but it can make demanding work feel sluggish. Blocked vents, dust, a warm room, or a worn cooling fan can make throttling happen sooner.

It is slow from the start

Heat may not be the main cause, especially if the laptop has just started and feels cool. A busy app, a power-saving setting, or a problem with storage or memory can also make a laptop slow. Check which apps are using the processor, and see whether the slowdown happens when the laptop is cool too.

The test does not make it slow

The laptop handled this short load without an obvious slowdown. That does not rule out a heat problem during a longer gaming session, while charging, or in a warm room. If the problem only appears in one app, check that app's workload and settings as well.

How to keep it from slowing down

1. Give the vents room to breathe. Use the laptop on a desk or another hard surface, not a bed, blanket, or your lap. Avoid covering the sides or underside where its vents are located.
2. Close the app using the processor. On Windows, press Ctrl + Shift + Esc to open Task Manager, then check the CPU column for apps using a lot of processing power. On macOS, open Activity Monitor from Applications, then Utilities, and check the CPU tab. Close only apps you recognize and do not need.
3. Check the power mode. On Windows 11, open Settings › System › Power & battery › Power mode. A lower-power mode can reduce performance. On a Mac, open System Settings › Battery and check whether Low Power Mode is enabled. Available choices depend on the Mac model and macOS version.
4. Let it cool before heavy work. Save your work, close demanding apps, and give the laptop time to cool. If it only becomes slow after a long gaming or editing session, take breaks and reduce demanding graphics or processing settings.
5. Restart the laptop. A restart can stop a stuck process that keeps the processor busy. If the fan stays loud and the laptop stays slow right after restarting, check for an app or system update using a lot of resources.
6. Clear dust carefully. Turn the laptop off and unplug it before cleaning around the vents. Use a soft brush on the outside, and do not push objects into the openings. If dust is inside the case, follow the manufacturer's cleaning instructions or ask a repair professional.

When it may be a hardware problem

A hot laptop that repeatedly shuts down, shows temperature warnings, or has a fan that grinds, rattles, or never spins up needs attention. A fan failure or dust packed inside the cooling system may require opening the case, which can be difficult and may affect a warranty. Check the manufacturer's warranty and service guidance before attempting an internal repair.

If the laptop is swelling, especially around the trackpad or case, stop using it and unplug it if you can do so safely. A swollen battery needs professional service, not cooling or pressure.

Why a laptop slows down when it is hot

The processor and graphics hardware produce heat while working. A cooling system moves that heat away, but it has limits. When temperatures approach those limits, the laptop can lower the hardware's speed to avoid damage. The case may still feel warm even when the cooling system is working normally, so warmth alone does not prove that something is broken.

Test under ordinary conditions, and compare the laptop when cool with how it behaves after a few minutes of work. A repeated slowdown as it heats up is a reason to check airflow and cooling, not to keep running stress tests.