• PC World
• »Computers
• »Desktops

When Gateway introduces its new desktops in September, among them will be a consumer model using a chassis design touted by Intel. Gateway executives say they expect their desktops to be among the first built using Intel's BTX reference design.

Heat Reduction

Intel has talked up the BTX (balanced technology extended) reference design at several of its Intel Developer Forum conferences over the past year. The updated chassis and motherboard design replaces the current ATX design, and allows PC manufacturers to deal with the ever-increasing amount of heat put out by modern components, says Ken Loyd, senior director of business marketing for Gateway.

As the clock speeds of Intel's flagship desktop Pentium 4 processor have increased, so has the heat given off by that processor. Intel warned system designers in February that the latest version of the Pentium 4, the 90-nanometer Prescott core, consumes upward of 115 watts of power under maximum operating conditions. Advanced Micro Devices' Athlon 64 chips also consume a lot of power, up to 89 watts under certain conditions.

At 90 nanometers, you can expect increased current leakage, which means that more power escapes the chip as heat than in previous designs. As Intel takes the Pentium 4 across the 4-GHz line next year, desktop builders will need to find a way to get that potentially damaging heat out of the system chassis.

Dual-Fan Cooling System

The BTX design uses two fans, one at the front of the chassis and one at the rear. A steady stream of air is directed through the chassis from front to back, passing over the processor and chip set.

These fans are larger than the single fans used in ATX designs, so they can turn at slower speeds. They're also quieter: BTX desktops should put out less than 40 decibels, about 10 decibels less than current designs, Loyd says. A BTX desktop would then be as loud as the humming of a refrigerator, according to information from the National Institute of Health's Web site.

The new BTX specification also addresses the placement of individual components on a PC's motherboard. Graphics cards and other powerful expansion cards plugged into PCI slots are notorious for the amount of heat they produce. Those cards have been rotated so that they face up into the stream of cool air, unlike previous designs in which the heat given off by those cards was directed down to the base of the chassis.

Another design improvement: Memory chips now sit parallel to the flow of air. Previously the placement of those chips in older ATX chassis and motherboards would have blocked the airflow passing through the system.

BTX motherboards will be available in three flavors: BTX, MicroBTX, and PicoBTX designs. Standard tower PC systems will use BTX motherboards, which are a maximum of 325 millimeters wide. Small and compact PCs will use MicroBTX and PicoBTX, respectively. The MicroBTX boards are a maximum of 264mm wide, while the PicoBTX boards are a maximum of 203mm wide.

Seeking Cooler Systems

Some gamers and PC enthusiasts with best-in-class processors and graphics chips have already faced heat problems and beaten them with liquid-cooled PCs. Apple Computer's newest PowerMac G5 uses liquid cooling in the most powerful configuration of that system, but most liquid cooling designs are viewed as too exotic and expensive for the mass market at the present time.

Gateway will release a consumer PC in September with the BTX technology, and in October it will use the BTX technology in a business desktop that will also feature Intel's latest 915 chip set, Loyd says. A spokesperson for Hewlett-Packard was unable to comment on unannounced products, and a spokesperson for Dell did not immediately return a call requesting information about BTX PCs.

Intel is expected to eventually shift its processors away from the heat of the current Pentium 4 design to an architecture that builds on the cooler operation of the mobile Pentium M processor. The company has not confirmed such plans, but it does intend to introduce dual-core designs next year that will present additional heat-related challenges for system designers.