Symptoms
- CPU temperatures have crept up compared to when the system was newer
- Cooler and fans are clean, but temperatures are still higher than expected
- System is several years old and has never had the paste replaced
- Fans run louder than they used to for the same workload
Likely causes
- CommonOriginal thermal paste has dried out and lost its heat-transfer effectivenessThis is expected after a few years and isn't a sign of a defect.
- PossiblePaste was applied unevenly or too thin/thick during the original installImproper application from the start can cause premature performance loss.
- PossibleCooler mounting has loosened slightly over timeReduced mounting pressure can also make the paste layer less effective.
What to do
- Confirm this is really a paste issue by first ruling out dust buildup and airflow with a basic cleaning.
- Power down, unplug, and remove the CPU cooler according to its specific mounting instructions.
- Clean off the old, dried thermal paste from both the CPU and the cooler's contact plate using isopropyl alcohol and a lint-free cloth.
- Apply a small, appropriately sized amount of fresh thermal paste to the center of the CPU (a pea-sized dot is typical for most CPUs).
- Reattach the cooler with even pressure, following the manufacturer's tightening pattern if screws are involved.
- Power on and monitor temperatures under load to confirm improvement compared to before.
Tools and parts
- Thermal paste
- Isopropyl alcohol (90%+)
- Lint-free cloths or coffee filters
- Screwdriver
Thermal pasteSearch: “CPU thermal paste”
When to call a pro
If you're uncomfortable removing the cooler, especially on a laptop or all-in-one, a repair shop can do a repaste quickly and safely.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.