Features

Spreading the Heat Around

High performance systems always run hot. That is just what happens when you pack the latest high-clock rate microprocessors alongside a blazingly fast graphics cards and spend all day doing compute-intensive tasks. Managing the heat these components generate is one of the primary challenges workstation vendors face. So far, a combination of heat sinks, fans, and well-managed airflow has enabled vendors to keep most workstations running cool, if not quite quiet. But if die sizes keep shrinking while clock rates keep increasing, vendor may have to look to new technologies to keep systems cool.

Unlike super-computers or server clusters, workstations are often used in the same workspace as the person using them. Because workers must co-exist with workstations in the same environment, there are limits to how cold the room can be and how many fans you can install on a system. The Xeon, Pentium 4, and Opteron chips require fan speeds in excess of 7000 rpm that generate noise of 60 decibels or more.

Excessive heat within a system can damage components, interfere with signal processing, and slow system performance. Maximum safe temperatures vary for different CPUs. Most Intel and AMD processor have official upper limit of approximately 800 C, but anything higher than 650 C could cause instability or permanent damage to your processor. Most over-clockers aim to have their processors operate at just 50-550 C under a maximum load, and much lower than that when idle.

In fact, according to Hewlett-Packard faster CPUs and faster hard drives have increased the system power requirements by approximately 50 percent in the last several years. All that heat has to go somewhere. Traditional passive means of cooling these chips, such as heat sinks and fans simple can't keep up. This is leading vendors to explore more active means of cooling the processor and reduce hot spots throughout the case.

Sinking Feeling

The most basic and fundamental cooling technology is the heat sink. Heat sinks conduct heat away from the processor and spread it out. Heat sinks are usually made from copper or aluminum, but the very best heat sinks combine the two. Copper weighs more than aluminum, but is has nearly than twice the heat conductivity of aluminum. That makes it great for carrying heat away from the processor. But copper doesn't radiate heat as well as aluminum. That is why many high-end sinks use copper to move heat throughout a sink and aluminum wings or fins to dissipate it.

Heat sinks come with just about every workstation shipped today, but they are also available from third parties in the aftermarket. Although the sink that came with your workstation should suffice, if you upgrade the processor you will want to check out a third party heat sink from companies like 2Cool or Coolermaster.

For its part, Intel is exploring ways to increase the efficiency of heat sinks using nanotechnology. Intel is conducting research with Zyvex, a nantechnology start-up, to create highly conductive thermal grease that contains carbon nanotubules. Thermal grease is used to attach heat sinks to the CPUs. The carbon nanotubules can dramatically increase the conductivity of thermal grease. Carbon nanotubules could offer 100 times the thermal conductivity of other metals.

Still, heat sinks alone are not sufficient for keeping a system cool. First of all, the heat generated by today's chips is pushing the effective limit of heat sinks. Plus, heat sinks are great for moving heat away from the CPU, but they don't do much to cool down the rest of the case.

To move hot air out of the case and cool air in, you need fans and a lot of them. It is not uncommon for workstations to come with several fans, one for the CPU, one for the graphics card, and one for the case. Some systems also come with separate fans for the power supply and the hard disk. Although most fans are regulated by the motherboard to spin only when the system heats up, workstations users should expect their fans to be running more or less constantly when in use.