I’ve got some Core 2 Duo-based servers since a while and thought I’d play a bit with frequency scaling. The board is a Supermicro PDSMI+ and the CPU is an Intel Core2 Duo E4400, running at 2GHz. However, when I modprobe acpi-cpufreq, the CPU frequency drops to 1000MHz, and indeed if you check the available frequencies in the /sys interface, all I see is 600, 800 and 1000 MHz. Anyone have an idea why? I guess the module gets it from ACPI tables or so, which are wrong? Or is there something else that needs to be set up… rmmodding acpi-cpufreq restores the CPU frequency to the correct 2000MHz.

Merry christmas, yada yada yada, greetings from Switzerland 🙂