Extreme cooling vital for your PC

Zatni Arbi, Columnist, Jakarta, zatni@cbn.net.id

Two things can get very hot inside your CPU casing: the power supply unit (PSU) and the processor. The PSU converts AC power to DC and provides protection against overloading and so on, and therefore it generates a lot of heat. The heat inside the PSU box is normally sucked out with a fan that you can find at the back of a CPU casing. Cooler air, which enters the casing through the air holes on the front panel, replaces the hot air and circulates to keep the PSU and the rest of the computer system at an acceptable temperature level.

It is more difficult to keep the processor from overheating, though. In the past, a fan would be attached to the top of the processor. Then a heat sink was used to absorb the heat from the processor more quickly. A heat sink is a passive device attached to the top of the chip, and it is usually made of aluminum or copper or both. A special thermal compound is usually applied between the heat sink and the processor to improve heat conduction. A fan is added on top of the heat sink for heat dissipation.

About two years ago I wrote about Elan Vital's air duct, which blows external air right into the heat sink. External air is always cooler than the air inside the casing, and therefore the air duct is more effective than just the heat sink and the fan that is attached to it. However, not many computers were equipped like this, at least until now. Generally speaking, a good, branded computer now is likely to include an air duct to blow the cooler, external air straight onto the PC's brain.

For several years, I had a minitower Compaq Presario that had this feature. Although the small casing was packed with cables and components, the machine never had any overheating problem although I normally left it running 24 hours a day.

In the future, as the processor's clock speed continues to increase, heat will become a bigger problem. Overheating will cause the system to hang or to reboot at its own will, causing us to lose our data. It will also shorten the useful life of the processor.

As the Pentium 4 processor breaks the three gigahertz barrier -- the recently introduced Intel Pentium 4 processor runs at 3.06 GHz, the chipmaker recommends adding an air duct.

"At this point, we can still use ordinary casing with high- quality fans," Budi Wahyu Jati, Intel's country manager for Indonesia, told me during the launch of the processor. "However, as the processor becomes faster, conventional cooling will no longer be adequate."

I guess designing a slim and sleek notebook will become harder and harder as the processors run faster. Intel will also have to work hard to produce high-speed Mobile Pentium 4 chips that do not require a complicated and battery-draining air circulation system. Luckily, both Intel and notebook makers have been quite good at this. * From passive to extreme

There are many ways to keep the temperature of the processor at a safe level. You can use a casing with multiple fans, for example. Enermax, a Taiwan-made all-aluminum casing, can be equipped with up to seven fans if you like (www.enermax.com.tw).

As its PSU already has two fans, you can have up to nine fans altogether. The casing is also a show item, as it features transparent sidewalls made of acrylic. The potentiometers on the front and rear panels allow you to adjust the fans' speed should the noise start to irritate you.

Using fans to keep everything inside the casing cool is considered the passive approach. A far more unconventional approach is to use water or other liquids to flush the heat off the processor. One example is the system from Koolance (www.koolance.com).

However, people do go to extremes when designing a computer's cooling system. Asetek Inc., a Danish company, for example, has been designing PC casings with a compressor, condenser, valve and evaporator to cool down the processor. The system, as you can see, is not different from what makes your fridge work. It is called VapoChill (www.asetek.com).

I had the chance to take a look at one of these casings, which was perhaps the only one in Jakarta. It was brought in by my friend Alfredo Hui from Astrindo Senayasa. I was told that the price of the casing, including the VapoChill, was about US$800, enough to buy two decently configured Pentium 4-based PCs.

What the VapoChill is capable of doing is reducing the temperature of a processor down to minus 35 degrees Celsius when the computer is not turned on. When it is powered up, the temperature can be minus 10 degrees. This may still be too cold for the processor, and therefore Asetek also includes two heating elements in the kit. One of them is to be placed underneath the motherboard where the processor slot is, and the other on top of the processor. Asetek has made sure that these elements -- and other parts in the included kit -- fit the processors with a high degree of precision.

The company admits that one of the few custom-made parts is the evaporator, which has to fit the processor properly. The evaporator absorbs the heat from the processor as it turns the refrigerant from the liquid phase into a gas. Another important component is ChillControl, the electronic controller that automatically adjusts the compressor as necessary. The board can be found on the right of the casing, and Asetek includes a utility to set the parameters.

What is this extreme cooling for? Overclocking, of course. Asetek claims that people have been using VapoChill to force microprocessors to run faster than their designated speed. For example, they have been able to run the new 3.06 GHz Pentium 4 at speed levels approaching 4 GHz.

Clearly, with a price this high, VapoChill is only for hardcore hobbyists or those who really demand maximum computing power. "Production houses that really require fast computers to vamp up their productivity may have to overclock currently available processors, and they will need a casing with effective cooling," said Alfredo.

If you buy a ChipKill, you will also need to buy the best motherboard that is capable of overclocking processors without causing instability. You will have to use the latest Intel Pentium 4 to maximize the benefits, and currently Intel is selling the processors in a quantity of 1000s for $675 each. Add to these the other "latest and fastest" components such as DDR333 memory and an ATA133 hard disk. Are you ready?