In the heat of . . . Pentium
But what got everyone's attention was the Prescott system chassis that Intel has shown developers, with a cooling system designed to dissipate 83 watts. In comparison, a standard light bulb, that can light a room, is 60 watts, and is too hot to touch when lit. Meanwhile, toy EasyBake ovens use 100-watt bulbs to let children bake miniature cakes.
Nor will the Prescott be the only heat-maker. A 3.2 gigahertz version of the mobile Pentium 4 is expected to be out by the end of the year, consuming 76 watts. A 2.5 gigahertz Celeron is also expected by the end of the year that will consume 61 watts. Even chipsets these days are said to consume about 15 watts. So it looks like extreme system cooling, previously the province of hobbyists who 'over-clocked' (reset their system clock speeds past the manufacturer's recommendations to achieve maximum performance) is going to become part of the mainstream.
Cooling
There are basically four ways to achieve processor cooling - not counting the use of a powerful chassis cooling fan, which can be assumed to be present. First, there are heat sinks. Previously, these were pieces of aluminum clamped atop the chip, with fins that radiated the heat into the air. These are seen today only in entry-level systems.
Next, there are combinations of heat sinks and fans. The fans are actually atop the heat sink, and suck air through the fins of the heat sink. Not only do they have to be wired for the fan's power supply, but these units frequently include places to attach heat sensors, both for temperature on the chip's surface and for the temperature of the air in the chassis. Aluminum, meanwhile, is no longer good enough for the heat sink - it has to be made of copper, which conducts heat better. And the copper has to be in a solid piece, since joints don't conduct heat as well. Instead of being cast in a mold, the fins are frequently cut with a saw. All these features drive up the cost of a heat sink/fan combination by a factor of 10, for $4 to $40.
Then comes water cooling. Water is piped to a jacket over the chip and then out of the chassis to a radiator. Such units are said to be able to dissipate heat about as much heat as a high-performance fan/heat sink, but generates almost no noise. However, it costs about three times more than a high-end heat sink/fan combination. Meanwhile, there are people who get nervous about the idea of pumping water into an electronic device.
At the high-end are devices that use the Peltier Effect, by which an electric current crossing dissimilar resistors can be made to conduct heat (the spot from which the heat is conducted becomes cold). Such devices amount to solid-state 'cooler plates' that are clamped directly atop the chip. Popular with hard-core over-clockers, these devices provide a silent solution - but cost four times more than regular cooling.
Keep the noise down
Meanwhile, there's cooling fans, and chassis makers have been showing boxes with air tunnels and conduits built in for maximum flow over the CPU. Others have dual fans in the back and two more on the side, over the CPU, and may have digital temperature gauges on the front of the case. Variable speed fans are also being seen more often, offering much quieter speeds when they are turned to their lower settings.
Hard-code users are assumed to know the safe temperature range of their machines, and will turn up the fans (and endure the noise) when doing processor-intensive work (such as video editing) and turn it down when doing less demanding work (like browsing or word processing.) At high speeds the fans can produce 50 decibels, enough to interface with normal conversation. Possibly for that reason, some predict that liquid cooling plumbing will become standard chassis fixtures for servers within a year - server farms could get uncomfortably noisy, otherwise.
We'll see where all this leads. In the meantime, stay cool.
Lamont Wood