Cooling it beyond cold
Liquid cooling systems usually use ordinary water; some use liquid nitrogen, which is about the coldest liquid there is (except maybe for Lake Tahoe in the early spring), around –196 degrees Celsius.

Water cooling systems, called waterblocks (see Figure 9-2), are available for CPUs, video processors, and chipsets. They do what you expect: circulate water in a closed system through a cooling agent and over the processor, where the water absorbs heat from the processor.


Figure 9-2: A CPU waterblock is the component of a water-cooling system that attaches to the heat sink and CPU.

Image courtesy of Swiftech

The most sophisticated systems used liquid nitrogen to cool the heat sinks and the processor. Just to frame a reference for you, water freezes solid at 0 degrees Celsius (32 degrees Fahrenheit) and boils at 100 degrees Celsius (212 degrees Fahrenheit). So –196 degrees Celsius is nearly 200 degrees (Celsius) colder than the temperature needed to freeze water. Obviously, this is not something you want to just cobble together for your PC.

See Chapter 6 for more information you need to know for the exam about the methods and devices used to cool a microprocessor.