Laptop overheating or slowing down when hot? Thermal throttling explained and fixed
A laptop that feels hot isn't necessarily in trouble, but one that slows down, stutters in games or switches itself off is protecting itself from heat. Most of the fixes are free.
What thermal throttling is
Processors and graphics chips speed up while they have cooling headroom and slow down (“throttle”) when they reach their temperature limit, so they never cook themselves. Throttling is a safety feature, not damage. The problem is that the laptop gets slow exactly when you need it: in games, video exports or a long video call.
What temperatures are normal?
| Situation | Typical CPU temperature | Verdict |
|---|---|---|
| Idle, browsing, documents | 35-60 °C | Fine |
| Video calls, light editing | 55-80 °C | Fine |
| Gaming, rendering, long exports | 80-95 °C | Normal for many laptops, especially thin ones |
| Hitting 95-100 °C and clock speeds falling | At the limit | Throttling; worth fixing |
| Hot at idle, or switching off by itself | - | Something's wrong: dust, a stuck process, a failing fan or dried paste |
The case itself typically feels warm (35-45 °C) on the underside under load. If it's too hot to rest on your legs, don't: besides blocking vents, it can cause skin burns over time.
How to check
- Windows: Task Manager > Performance shows the CPU speed in real time; watch it drop under load. HWiNFO (free) shows temperatures and flags “Thermal throttling: Yes”. Task Manager > Performance > GPU shows GPU temperature on most machines.
- Mac: Activity Monitor > CPU shows what's busy;
sudo powermetrics --samplers smcin Terminal reports thermal pressure on many models. - Linux:
sensors(lm-sensors) and watchinggrep MHz /proc/cpuinfo.
The fixes, in order
- Hard, flat surface. Most laptops pull air in from underneath. A bed, sofa, duvet or lap blocks the intakes and is the single most common cause. A cheap stand that raises the back a few centimetres helps further.
- Find the busy process. Sort Task Manager or Activity Monitor by CPU. Windows Update, antivirus scans, cloud photo syncing, indexing, a runaway browser tab or a crypto-mining extension can keep the CPU at full speed in the background.
- Clean the vents. Shut down, unplug, and blow short bursts of compressed air into the exhaust vents (usually at the back or side) while holding the fan still with a toothpick through the grille if you can, so it doesn't over-spin. Dust mats on the heatsink fins and can cut cooling dramatically.
- Power and fan mode. Windows Settings > System > Power > Power mode, plus the maker's app (Lenovo Vantage, ASUS Armoury Crate, Dell Optimizer, HP Command Center, MSI Center). “Best performance” or “Turbo” runs hotter and louder; “Balanced” is usually barely slower. Some apps have a “cooling” profile that runs fans harder, which is what you want for long gaming sessions.
- Cap frame rates in games. A game running at 200 fps on a 60 Hz screen makes the GPU work flat out for frames you never see. Cap to the screen's refresh rate or use V-Sync; heat, fan noise and coil whine all drop. See 60 vs 120 vs 144 Hz.
- Cooling pads help modestly (a few degrees) on laptops with bottom intakes; they do little for models that breathe through the keyboard.
- Replace the thermal paste (and on gaming laptops, the thermal pads) if the laptop is several years old and still hot after cleaning. The paste between chip and heatsink dries out; fresh paste often lowers load temperatures by 10 °C or more. It needs the bottom panel off and some care, so a repair shop is a fine option, and it may affect warranty on a new machine.
- Undervolting lowers the chip's voltage for the same speed, so less heat. Many recent laptops lock it for security reasons; where it's allowed (via the maker's tool or ThrottleStop), small steps and stability testing are essential.
Explaining this to someone younger? Wirebook has a free Cool the laptop game: seven overheating laptops (duvet, dust, stuck program, sun, dried-out paste) to fix in three moves or fewer, with the reasons each fix works.
Charging and batteries
Charging adds heat, and heat ages batteries. A laptop that's always plugged in and warm benefits from the maker's battery-care option that stops charging at about 80%. A swollen battery (case bulging, trackpad lifting) is a safety issue: stop using it and get it replaced. See laptop not charging while plugged in.
When to stop
If the laptop shuts itself off from heat even after cleaning, a fan may have failed (no sound or airflow from the vent when it's hot), or a heat pipe has come loose. Shutting down is again a protection, but it's time for a repair.
Related
Sound crackles when the laptop is busy · Touchpad not working or cursor jumping · Fan noise and coil whine · Game stutters even with high FPS · Laptop battery not charging · Second monitor not detected
Questions
What is thermal throttling?
The processor or graphics chip slowing itself down when it reaches its temperature limit, to avoid damage. It shows up as stutters, slow exports or games dropping frames when the laptop is hot.
How hot is too hot for a laptop CPU?
Under heavy load, 80-95 °C is normal for many laptops. Constantly hitting 95-100 °C with falling clock speeds means it's throttling, and anything above about 60-70 °C at idle suggests dust, a busy process or dried paste.
Do laptop cooling pads work?
A little: usually a few degrees on laptops that take air in from underneath. A stand that raises the back and a clean set of vents usually do more.
Should I replace the thermal paste on my laptop?
On a laptop over about three years old that's still hot after cleaning, often yes; fresh paste can cut load temperatures by 10 °C or more. On a new laptop under warranty, ask the maker first.
Why does my laptop get hot while doing nothing?
Usually a background task such as updates, antivirus, cloud syncing or a busy browser tab, or dust and a blocked intake. Check Task Manager or Activity Monitor sorted by CPU, and use it on a hard surface.
Published .