hardware fixes (AMD K6 in Socket 5 boards)


Socket 5 supportes only single voltage CPUs.

The two versions of the AMD K6-233 processor run at 3.2Vcore / 3.3V I/O and 3.3Vcore / 3.3V I/O settings. The last setting is precisely the same as Standard single voltage (3.3V across the entire chip). So it seems to make sense that the K6-233 may actually run in an older motherboard that can supply standard voltage even though it doesn't support split (dual-rail) voltages required by the chip.

In a few cases, this may be true.

However, the K6-233 is a serious power hog. The 3.2V version draws a maximum of 10.02 amps (9.5A core) and the 3.3V version draws a maximum of 10.27 amps (9.75A core). Considering that the original Socket 7 motherboard was designed for only 5.0 amps at 3.3 volts and subsequent versions that added multiple passive voltage regulators can often only handle 7~9 amps, putting the K6-233 into a motherboard that wasn't electrically designed for the CPU may not be the best idea. That kind of amperage can damage the motherboard. And it can really heat up those poor little passive regulators. So much so that they would actually require a fan of their own! Speaking of heat, the K6-233 puts off a tremendous amount. At its maximum (running at normal voltages but under the heaviest CPU load), the 3.2V chip dissipates 28.3 watts of power and the 3.3V chip dissipates 30.2 watts. This chip not only requires a good heatsink and fan, but also a computer case that has good airflow.

AMD supplies a list of K6 approved motherboards and also provides guidelines for motherboards that aren't on their official list. They also have a FAQ page on technical aspects of the chip. AMD also supplies documentation for the 3.3V version of the K6-233 which contains a short list of motherboards that meet the requirements of the chip. This document requires the Adobe Acrobat Reader. If your motherboard isn't on any of AMD's official lists, contact the motherboard manufacturer to see if its approved for the K6-233. Running the K6-233 at standard voltage in any old Socket 7 motherboard in any old case with any old power supply is not generally a good idea. Even though the voltage may be right (standard voltage falls within the nominal voltage range on both chips), the motherboard may still not be able to handle the amperage or deal with the excessive heat dissipated. It's probably best to avoid putting the K6-233 into older motherboards or even into the cheaper new ones. Pulling excessive amps through a motherboard that wasn't designed to handle it can damage the motherboard as well as the CPU itself.