How Liquid-cooled PCs Work

Cooling with Liquid: System Parts

These water blocks can cool a GPU, a CPU and a northbridge.
These water blocks can cool a GPU, a CPU and a northbridge.
Image courtesy Darrin Gatewood

A liquid-cooling system for a PC is a lot like a cooling system for a car. Coolant flows through channels in a car's engine block, and the rest of the cooling system incorporates:

  • A pump that moves coolant through the system
  • A radiator that dispels heat into the air
  • A fan that moves air over the radiator
  • A coolant reservoir that holds extra fluid and allows easy addition of coolant
  • Hoses that connect the different parts of the system

Many electronic components do not tolerate direct contact with liquid. So instead of using channels to pump liquid directly through microchips as in a car engine, a liquid-cooled PC uses water blocks. A water block is a piece of heat-conductive metal, like copper or aluminum, that's filled with hollow tubes and channels. The bottom of the water block is a flat piece of metal that sits directly on top of the chip being cooled. Thermal paste between the chip and the block improves the heat transfer between the two surfaces. The chip heats the block, and the water absorbs the heat as it flows through all the channels.

Many central processing unit (CPU) water blocks are universal, but some graphics processing unit (GPU) water blocks only work with specific chips. You can also find water blocks designed to cool other high-temperature chipsets, like the northbridge, which connects your CPU to your memory. Usually, small bolts and washers attach the water block to the necessary printed circuit board (PCB), such as the motherboard or video card.

The rest of a liquid-cooling system's components are much like those found in a car's cooling system. On the next page, learn about the liquid cooling pump.