Computer Running Hot? Causes, Warning Signs and Fixes
Computers generate heat as a byproduct of processing. Within normal limits this is fine — but excessive heat causes slowdowns, crashes and long-term hardware damage. Here is everything you need to know.
What temperature should a CPU run at?
For most processors, 30 to 60 degrees Celsius is normal at idle and 70 to 85 degrees is acceptable under load. Temperatures above 90 degrees are concerning. Above 95 degrees is where modern CPUs start automatically slowing down to prevent damage. Monitoring temperatures during normal use reveals whether overheating is a problem.
Why computers overheat
The most common cause is dust. Over time, dust accumulates in fans and heatsinks, blocking airflow and trapping heat. Other causes include dried-out thermal paste between the CPU and heatsink after five or more years, a failing fan, running demanding software for extended periods, or using a laptop on soft surfaces that block vents.
Signs your computer is overheating
The fan running at full speed constantly. Performance dropping gradually during intensive tasks — this is thermal throttling. Random shutdowns or restarts with no warning. The computer is very hot to touch around the exhaust vents. Crashes specifically during demanding tasks but not during light use.
How to check temperatures
On Windows, free tools like HWiNFO or Core Temp show CPU and GPU temperatures in real time. On Mac, Activity Monitor shows some temperature data, and tools like iStatMenus give full readings. Cerebro Scan displays temperature readings on its Processor tab. Monitoring temperatures over time reveals whether overheating is causing performance issues.
Fixing an overheating computer
For laptops: clean the vents with compressed air — do not poke anything inside. Use a hard flat surface or a laptop stand. For desktops: open the case and carefully blow out dust with compressed air. If temperatures remain high after cleaning, the thermal paste between CPU and cooler may need replacing — most repair shops can do this for around £20 to £40.
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