The issue of diminishing Pentium 4 CPU performance at overheating has been widely discussed (see, for example Intel Pentium 4 1.6A GHz Overclocking, Thermal Monitor). Still, there are all sorts of myths about the Thermal Monitor and Thermal Throttling technology. That is why we decided to refresh our practical knowledge in this field (dropping the theoretical aspect which is abundant in the above-mentioned articles). For this purpose, we conducted a very simple experiment on two top Pentium 4 3.2 GHz CPUs, one with a Northwood core and the other with a Prescott. With the CPU loaded at 100 percent, we powered off the cooler fan and watched the temperature rise and the performance decrease as time went by. This article gives an account of the experiment and its results.

The Throttling Intel Experiment