In the quest for ever faster silicon, heat is the number one barrier to performance. This is because most processor chips can be fairly easily forced to run at more than their official operating speed, but a higher processing speed means more heat is produced. If a processor is not kept cool, it can be permanently damaged by overheating. There are other problems that face high-speed computers as well, but heat exacerbates them all.
That's why overclockers - hobbyists who tinker with their computers to make them go faster than their rated speed - are obsessed with cooling their chips. Extra fans in the case, large aftermarket heatsinks, solid state Peltier heat pumps, even liquid baths have all been used in the pursuit of performance. Kryotech is a company that has turned the experiments of geeky hardware hackers into a respectable business, and its high-powered cooling products find their way into some major companies.
The secret to Kryotech's cooling technology is no mystery - it's the same as that used in a household refrigerator. In fact, it even uses standard refrigerator parts, though some components like the KryoCavity are custom made.
Kryotech's system is based on a simple physical fact: when you compress a gas, its temperature increases, and when you decompress a gas its temperature decreases. A compressor, seen in the illustration, compresses the refrigerant gas which fills the pipes, causing it to release heat. The gas is passed through a condenser, which cools it down by passing on heat to the surrounding air. From here, the refrigerant, now a liquid at near room temperature, is piped to the KryoCavity which surrounds the processor.
The KryoCavity has two main components: an evaporative cold plate clamped to the processor's surface, and an insulated box which surrounds the processor. When the refrigerant reaches the cold plate, it picks up heat from the chip, and at the same time it is allowed to expand. The refrigerant changes from liquid to gas and becomes much colder, absorbing heat from the processor. It then returns to the compressor, where it will begin the cycle again, in the process transferring the chip's excess heat to the atmosphere through the condenser.
The end result is that the processor is cooled to a temperature of -40ºC, allowing an 800MHz Athlon part to run safely at 1000MHz. Because of the insulation around the processor, the surface of the KryoCavity doesn't get cold. In fact, this box actually contains heating elements, which are used to keep the outside warm enough to prevent condensation forming, since nobody likes water on the motherboard.
The power supply is connected to the cooling system so that when you turn on the computer, the compressor runs until the processor has reached operating temperature before power is delivered to the motherboard, which takes about 30 seconds. After power down, the system stays active long enough - about four minutes - for the heating elements in the KryoCavity to bring the processor back up to room temperature.
At the moment, the Athlon is the processor of choice for this type of machine, but the technology can be applied to any computer. Now that Intel's Coppermine series of improved Pentium III processors has hit the market, we can probably expect to see a Kryotech model that supports these any day now.