Cleaning, cooling and thermal paste – looking after your computer

Why dust is a problem

Coolers carry heat away through thin metal fins. Dust settles on them like felt and blocks the airflow. The fans then spin faster (noise), and when even that is not enough, the processor or graphics card reduces its performance so as not to exceed its maximum temperature. For the Ryzen 9 9950X, AMD gives a maximum operating temperature of 95 °C; for the Core Ultra 9 285K, Intel gives 105 °C. These chips routinely approach their limits under load – that is normal as long as performance does not drop.

How to clean a desktop PC

1. Shut it down, unplug it, and press the power button to discharge any residual charge.
2. Remove the dust filters and wash them or blow them out.
3. Use compressed air to blow out the CPU cooler, the graphics card and the power supply – towards the outside of the case. Hold the fan still with a finger or a plastic stick so the airflow does not spin it beyond its normal speed.
4. Do not touch the inside of the power supply beyond blowing it out from the outside – it contains high-voltage capacitors.

Laptops

Laptops have small fans and dense fins that clog up faster. If the bottom cover can be removed without voiding the warranty (see the service manual), you can do the cleaning yourself. Otherwise, try blowing compressed air into the exhaust vents with the laptop switched off, or take it to a repair shop.

Airflow in the case

Fans have arrows on the frame: one shows the direction of airflow, the other the direction of rotation. A typical layout: the front fans draw air in, the rear and top fans exhaust it. If the fans are blowing against each other, the air just swirls around inside the case and no heat is removed.

Thermal paste

Always replace the paste between the processor and the cooler whenever you take the cooler off – the original layer is broken once they are separated. Otherwise, replace it if temperatures under the same load stay noticeably higher than they used to be, even after cleaning.

• Remove the old paste with a lint-free cloth and isopropyl alcohol.
• Apply a small amount (a pea-sized dot or a thin cross) in the centre – the pressure of the cooler will spread it.
• Graphics cards and laptops may use thermal pads of a precise thickness instead of paste. Do not replace them with paste.

At the end of its life

If the computer is no longer worth repairing, hand it in as electrical waste. Under the Slovak Waste Act, Act No. 79/2015 Coll. (zákon č. 79/2015 Z. z. o odpadoch), you can hand it to the retailer when buying a new device of the same kind (one for one), take it to your municipality’s collection point, or give it to an authorised collector. It does not belong in general household waste. Details are in the guide Right to repair and e-waste.