Friday, January 16, 2009

Way of Installing an AMD Athlon or Duron Socket A Processor.

Introduction. Many AMD Socket A Athlon and Duron processors are damaged during installation. The purpose of this article is to help you avoid that misfortune.

An AMD Tech Tip regarding Socket A heatsinks states:

"The new exposed flip-chip design of the PGA AMD Athlon and AMD Duron processors requires a clip [heatsink spring] load between 12 and 24 pounds (typically 16 pounds), a load that may not be met by most older heatsink designs." [e.g., Socket 7 heatsink-fans]

"New PGA (Pin Grid Array) AMD Athlon(tm) and AMD Duron(tm) processors have very different thermal specifications than any preceding AMD processor? Due to these differences, the AMD Athlon and AMD Duron processors should NEVER be run without a heatsink, not even for a few seconds. Doing so will cause the processor to overheat and fail immediately, resulting in permanent damage. While testing a processor by booting it up for several seconds without a heatsink installed may be common industry practice, it should never be attempted with the new PGA AMD Athlon and AMD Duron processors."

Also, improper installation of the heatsink on the processor can exert too much force on the CPU (Central Processing Unit or Processor) die (the little rectangular thing in the middle of the processor--the actual chip) and damage it--crack the stuff holding it to the rest of the processor.

How AMD Socket A Processors are Packaged. One can buy two basic flavors of AMD Socket A Processors: OEM (Original Equipment Manufacturer or a company that makes things such as computers) and PIB (Processor in a Box or retail version). Both versions are widely available (but not always available). The OEM version comes without a heatsink-fan and the PIB version comes with the heatsink-fan, but it is not already attached to the CPU like the AMD K6-2 PIB processors.

Heatsink Compound. A 1 GHz Athlon generates about 50 Watts of heat, or about half that of a incandescent light bulb. Most of the heat is coming from that little bitty die. Thermal compound between the die and the heatsink is therefore absolutely essential for Socket A processors. It fills-in microscopic imperfections (scratches, pits, etc.) on the surface of the die and on the bottom of the heatsink to eliminate air pockets which are poor thermal conductors. Improper application of the compound or inferior compound can fry your CPU, damage your motherboard, corrupt data, and cause other problems, such a computer rebooting itself on a hot summer day.

There many kinds of thermal compounds used with CPU heatsinks. Among them are various kinds of silicon and non-silicon grease, adhesives, thermal pads, double-sided tapes, and thermally applied compounds Adhesives, epoxy or acrylic, permanently bond the heatsink to the CPU. Thermally applied compounds fill scratches and eliminate air pockets through a phase-change process which occurs when the CPU first heats-up. Phase-change material is usually applied to the bottom of the heat sink and protected with a removable film during manufacturing. For more information see Heat-sink-attachment methods optimize thermal performance.

Thermal greases typically provide the best thermal conductivity. They consist of binder (silicon, etc.) and a metal or metal oxide which conduct the heat. Some of them are conductors of electricity and others are not. Those that are not electrical conductors can have capacitive properties which can affect the operation of electronic components. Thermal greases are cost effective, but can be messy to apply and difficult to clean-up. I have also read thermal grease may degrade over time, but have not seen it in the real world.

We will use the thermal grease that came with the heatsink-fan as an example in this article. It was manufactured by Stars, is similar to the stuff sold at Radio Shack, and has more liquid consistency than the paste-like Shin-Etsu G749 thermal grease used with a Slot 1 Athlon in our Build Your Own Athlon Computer (Slot 1 CPU) article.

Some readers who like to do things with processors (e.g., overclock/overcook them, which I do not recommend) may want to use a higher performance heatsink-fan and a heatsink compound with a higher thermal conductivity, such as Artic Silver. The PIB version of the CPU comes with a thermal compound already applied to the bottom of the heatsink. If another thermal compound is to be used, than that pad must be completely removed from the bottom of the heatsink.

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