Laptop overheating: why your machine got slow, and the cheapest fix in repair

Heat does not crash your laptop. It slows it, silently.

Modern CPUs and GPUs protect themselves. When the die reaches its thermal limit — typically 95–100°C — the chip lowers its clock speed until it stops getting hotter. No error appears. Nothing is logged where you would see it. The machine simply runs at a fraction of the speed you paid for, and you conclude it has aged.

This is why "my laptop is slow" and "my laptop is hot" are the same complaint far more often than people realise, and why reinstalling Windows fixes neither.

The four things that actually degrade

1. The fin stack clogs. Singapore's air is humid and dusty. Dust mats across the radiator fins like felt, and the fan pushes air that has nowhere to go.
2. Thermal compound dries and cracks. The paste between the CPU die and the heatsink loses its conductivity over three to four years. On liquid-metal machines it can pump out from under the die entirely.
3. Thermal pads harden. VRM and VRAM are cooled through silicone pads of specified thickness. They stiffen, lose contact and stop conducting. Almost every cheap 'repaste' ignores them.
4. Fan bearings wear. A worn fan spins slower under the same drive signal but still reports an acceptable tachometer count, so no warning appears. Airflow collapses quietly.

Diagnosing it yourself in ten minutes

Install a temperature monitor and run a sustained load — a game, a video export, or a stress test — for fifteen minutes. Watch three numbers: peak temperature, sustained temperature after ten minutes, and clock speed at the end.

• Sustained above roughly 95°C with clocks dropping — you are thermally throttled. Book a service.
• Hot immediately, from idle — suspect a fan that is not spinning at all, or a heatsink that has lost contact.
• Fan loud but exhaust air cool — classic clogged fin stack. The heat is not reaching the fins.
• New whine or rattle — bearing wear. Replace the fan; do not oil it.

If you see artifacts, crashes in 3D, or a black screen with fans spinning, stop. That is heat that has already done structural damage to a GPU's solder joints, and every further hot cycle makes the reball harder.