Now a little on the technology that drives the TAC.

Currently, there are two versions to Thermally Advantaged Chassis. More specific information with regards to the version of TAC can be found on Intel’s site.

Version 1.0

The first version of Thermally Advantaged Chassis, it sports a single circular side duct that allows surrounding air to be supplied to both the system and processor. The specifications were first released in May 2002.

Recommended rear system fan has to be at least 80mm in diameter.

v1.0 Intel Pentium 4 Processor with 1MB L2 Cache & Thermally Advantaged Chassis
Drawout of the Thermally Advantaged Chassis Version 1.0. (Image courtesy of Intel)

Version 1.1

Version 1.1 is a revision to the older Version 1.0 and was released in September 2003. The significant difference between Version 1.1 and Version 1.0 is the extra add-in card side vent. This vent acts as a system inlet and provides air through the add-in cards. Higher performance graphics card will benefit by having this lower temperature air as input to the existing cooling solution.

Changes in Chassis Design Guide version 1.1 also includes an increased side vent duct diameter and a recommendation to increase the rear chassis fan size to 92mm or greater.

v1.1 Intel Pentium 4 Processor with 1MB L2 Cache & Thermally Advantaged Chassis
Drawout of the Thermally Advantaged Chassis Version 1.1. Note the extra add-in card side vent. (Image courtesy of Intel)

The Chassis Air Guide

The chassis air guide is divided into three seperate components

  • Upper Duct
  • Flange
  • Lower Duct

For ergonomical purposes, the three stage air duct was proposed. The design is meant to cater to different widths in different chassis and the ducts can be elongated simply by the use of the hand. The flange piece is screwed onto the side panel of the chassis to add support to the uppder duct.

duct Intel Pentium 4 Processor with 1MB L2 Cache & Thermally Advantaged Chassis
Setup of the air duct (Image courtesy of Intel)

The theory behind the Thermally Advantaged Chassis is explained in the following diagram.

chassisairguide Intel Pentium 4 Processor with 1MB L2 Cache & Thermally Advantaged Chassis
Explanation of how the cooling works for TAC. (Image courtesy of Intel)

The rear exhaust fan and power supply fan reduce the pressure of the chassis internals. Higher atmospheric pressure outside of the chassis causes air to rush into the chassis air guide. The now accelerated air is drawn effectively into the processor active fan-heatsink. This creates a steady flow of cool air, providing more effective cooling to both the processor and the system.

To facilitate an ideal condition for cool air to flow through the air duct, a distance of 12-20mm must be maintained between the lower duct and the processor fan heatsink. There are two main reasons behind this. If the distance is more than 20mm, most of the incoming cool air will escape and the main beneficiary will be the system. This, as a result, will deprive the processor of the cooling it needs. The processor is one of the hotter components found inside a computer and such a scenario is highly undesirable. On the otherhand, should the distance be less than 12mm, most of the cooling will be credited to the processor and the system will, as a result, be starved from having sufficient cooling.

Researchers over at Intel derived that at a distance of 12-20mm, both system and processor strike a balance and benefit from this huge in-flow of cool air.

TAC3 Intel Pentium 4 Processor with 1MB L2 Cache & Thermally Advantaged Chassis

Illustration of the distance between the duct and fan heatsink (Image courtesy of Intel)