Adding thermal paste to your CPU allows heat to flow more easily from the processor to the cooler. This helps ensure that the CPU does not overheat, which can damage it or reduce its lifespan.
The best thermal pastes will have a high thermal conductivity, meaning they can move heat faster from the hot spot to the cooler. They will also have a low specific gravity, which means they are less dense and heavier than other thermal compounds.
A lot of the top contenders here are ceramic-based. This is because they are typically non-corrosive and safe to use, which makes them great for high-performance PC builds. The thermal grizzly Kryonaut and the Arctic MX-4 are examples of excellent ceramic-based products that offer excellent performance.
Another popular option is the CORSAIR MasterGel Pro v2. It has a mild viscosity that is easy to work with and will resist drips or runs. This product is designed to be used in many different types of systems, but it is primarily targeted at people who want to overclock their processors.
One of the more recent additions to this list is the Cooler Master CyroFuze Violet. This product was just released this year and it is a high-end blend that is supposed to have fantastic conductivity. CM mentions that their special composition is infused with carbon particles and is metal & silicone free.
The one downside to this paste is that it dries out more quickly than some of the other options on this list. However, it still does a good job and is a solid choice for people who want a thermal paste that performs well in general but doesn’t require constant replacement. High-performance thermal paste