Thermal Paste for CPUs and GPUs

Conductivity ratings versus what you can see on a chip

Listings quote thermal conductivity in W/mK, and figures from 8.5 up to 20 or more look like a clear ladder. They are not, because each maker measures differently and a good paste on a well-mounted cooler gains only a few degrees over a decent one. Treat the number as a rough guide, then look at the temperature range, consistency and whether the pack includes a spatula and wipes.

The very highest figures usually belong to liquid metal, which conducts electricity, so a stray drop beside the chip can short components on the board, and a few metal-filled pastes conduct too. Liquid metal also reacts with aluminum, so it belongs only on copper or nickel-plated surfaces. Ceramic or silicone-based pastes sold as non-conductive are the forgiving choice for a first build; check the listing for that wording.

Pack size, pads and how long a tube lasts

A single processor needs only a pea-sized amount, roughly 0.1 to 0.2 grams, so small tubes cover several applications and large tubs suit repair benches or frequent upgrades. Check the continuous-use temperature range if the part runs hot, such as a graphics chip or an overclocked processor. Very small syringes are enough for one cooler, while a bulk tube makes sense if you service many machines and want to avoid running out.

Thermal pads are a different tool: they fill larger gaps over memory chips and voltage regulators where paste would be too thin. Pick the thickness that matches the gap, and clean off old paste with isopropyl alcohol before reapplying. Dry, cracked or pumped-out paste is a sign that it is time to redo the job.

Questions about Thermal Paste for CPUs and GPUs

How much thermal paste should I use?

A pea-sized dot or small line, about 0.1 to 0.2 grams, is enough for a desktop processor. Too much squeezes out and can make a mess, while too little leaves gaps that raise temperatures.

Is liquid metal safe for beginners?

It is riskier. Liquid metal conducts electricity and can short nearby parts, and it damages aluminum. Beginners should use a non-conductive paste, which is far more forgiving if a little spreads past the chip.

How often should I replace thermal paste?

Every few years, or whenever you remove the cooler. Replace it sooner if temperatures climb over time or the paste looks dry and cracked. A fresh layer restores contact between the chip and the heatsink.