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LAS VEGAS--An Israeli company here at Comdex is showing an inexpensive prospective answer to the problem of CPU heat control: a user-installable thermoelectric heat pump that leads to quieter system operation.

The AC4G cooling system from Active Cool is said to maintain CPU temperatures at 72 degrees even during processor-intensive operations and result in significantly lower CPU fan noise. The company claims that users can install the $120 product in less than 90 seconds in any PC that uses at least an Intel Pentium 4 or AMD Athlon processor.

The product was unveiled in October and is being shown here this week. Taiwanese manufacturer Thermal Take will begin marketing it in January.

Running Hotter

Gamers and high-end PC users have long recognized the value of keeping their processors cool. Applications for image manipulation and graphics-intensive games can cause CPUs to overheat, in some cases corrupting data or crashing the system. To get around this problem, Intel's P4 CPUs employ a Thermal Control Circuit (TCC) that slows the processing speed of an overheating CPU to prevent damage.

This situation will become even more problematic as CPUs move beyond 3.4 GHz, according to Active Cool. The demand could drive current fans and heat sinks beyond the limits of their cooling capacity, says Ronen Meir, Active Cool's CEO.

High-end users are already turning to exotic answers to heating problems, such as liquid cooling and vapor-phase refrigeration systems. Both of these techniques are effective but costly, and they usually require custom installation.

How It Works

The AC4G product actually consists of two major parts: a power supply and the cooling unit itself, which is topped by a small fan. The power supply plugs into an open PCI slot. An external plug supplies current, while a smaller plug connects to the cooling unit. A microprocessor in the power supply receives input from both ambient temperature and CPU temperature sensors. The microprocessor samples temperatures and adjusts the cooling power of the thermoelectric unit and of the CPU fan atop the cooling device. It can also power a separate case fan if desired.

The cooling unit consists of a cold plate, a high-power custom thermoelectric unit, a heat sink, and a fan. The cold plate sits directly on the CPU, while the thermoelectric unit pumps heat from the cold plate to the heat sink. The CPU fan draws off heat that accumulates in the heat sink.

Because the thermoelectric unit is doing most of the cooling work in the system, the CPU fan typically runs at half-power, drastically reducing noise.

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