Answer:
Thermal paste (or thermal grease) is a thermally conductive compound which forms a seal between the CPU/GPU heat spreader and the heatsink in order to transfer heat more efficiently.
Thermal pads serve this same purpose, but they are made of solid material such as silicon. This makes them easier to place and replace, but they also aren’t quite as efficient and don’t last as long as thermal paste.
Like any other machine that generates heat, computers need cooling. This could be active air or liquid-based cooling for components like the GPU and the CPU, which are responsible for most of the heat generated by a PC, or it could be simple heatsinks and heat spreaders such as those you see on motherboards or on RAM sticks.
Now, for cooling to be efficient, heat must be transferred from the component to the heatsink, and this is where terms such as thermal paste, thermal grease, and thermal pads come in.
So, what are these, and what are the differences between them?
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What Is Thermal Paste/Thermal Grease?
First and foremost, we’d like to point out that thermal paste and thermal grease are the exact same thing that has a variety of different names apart from those mentioned above. These include thermal compound, heat paste, and heatsink paste, among others, though thermal paste is the one that you’ll probably encounter the most.
So, what is thermal paste, and what does it do?
As mentioned above, for cooling to be efficient, heat must be transferred efficiently from the component, which generates it to the heatsink. Now, the surfaces of CPU/GPU heat spreaders and heatsinks aren’t perfectly smooth and level. This results in pockets of air being trapped between them.
And since air is terrible at conducting heat, these air pockets can significantly impede cooling efficiency, and that is the problem which is resolved with the help of thermal paste.
Namely, thermal paste is a thermally conductive compound which forms a seal between the surface of the CPU/GPU heat spreader and the surface of the heatsink. It fills up all the microscopic gaps in the metal, thus eliminating air pockets and ensuring much more efficient heat transfer.
But as usual, not all thermal pastes are identical, as some are inevitably more efficient than others. To be more specific pastes that conduct electricity i.e., those that are metal-based or contain traces of metal, are the most thermally conductive. However, this means that they could also potentially lead to some hardware damage e.g., if too much paste is used and it ends up getting into the CPU socket.
On the other hand, you have pastes that don’t contain metal and don’t conduct electricity, and these are usually carbon or ceramic-based. They are safer to use as there is no risk of hardware damage, which might make them more appealing to those who are new to PC building or just plain paranoid.
On the downside, these also don’t transfer heat as efficiently, but are still more than efficient enough for most PCs, as having your CPU run a few degrees hotter won’t make much of a difference unless you’re doing some heavy overclocking.
What Are Thermal Pads?
Then, we have thermal pads, which serve the same purpose as thermal paste. However, they differ in that they are solid sheets of a thermally conductive material such as silicon, which has a few implications.
The main benefit of thermal pads is that they are easier to place and replace – they are cut to size based on your needs. You don’t need to worry about whether you’re using too much or too little paste, plus there is no need to clean up the old dried-up paste from the heat spreader and the heatsink once it’s time to replace it.
However, the obvious downside to thermal pads lies in the fact that they are made of solid material. Therefore, they cannot completely fill up the microscopic gaps in the metal like thermal paste can, which means that they will be less efficient overall. On top of that, they also need to be replaced more often than thermal paste.
That said, thermal pads are great for those who are new to PC building or perhaps just those who hate cleaning up old paste or re-applying it every time they remove the cooler to clean it.
In any case, thermal pads used to be more prevalent in the past, but you’ll rarely see anyone using them for CPU or GPU cooling these days, although graphics cards manufacturers still often use them for VRAM cooling.
Conclusion
So, to summarize: thermal paste and thermal pads are both composed of thermally conductive material that enhances cooling efficiency by allowing for more efficient transfer of heat to the heatsink from the component which generates it.
Overall, thermal paste is more efficient and doesn’t need to be replaced as often, whereas thermal pads are less efficient but they’re easier to place and replace, though they also need replacement more frequently.
Price-wise, there are no big differences to keep in mind. Thermal paste prices generally range from $2 to $15, while thermal pads tend to be a bit cheaper on average but as mentioned above, they also need to be replaced more often. That said, thermal paste would probably be a slightly more cost-efficient choice, but considering the prices, it’s not like you can save much by skimping on either.
On a final note, if you’re shopping for new thermal paste right now, we suggest checking out our selection of the best thermal pastes currently available. Moreover, if you’re struggling with components running very hot, you should consider adding some case fans or replacing the CPU cooler.
