Comment 35 for bug 132271

As somebody who used to be affected by this bug, I can say with a reasonable level of certainty, that your BIOS (in particular the ACPI code) is buggy. The speedstep-centrino frequency table hack was marked as deprecated in an earlier kernel (sometime around 2.6.18), and newer kernels use ACPI for setting frequency/voltage. This is not Ubuntu's fault. If you want to complain to someone, look further upstream to the kernel developers - but good luck, because I doubt they'll listen. The real bug lies with your BIOS vendor, and flaky ACPI code.

If you want to mimic the behaviour of Feisty, look to the linux-phc project at https://www.dedigentoo.org/trac/linux-phc/

This is essentially the patch that the Ubuntu kernel team added, to ensure frequency scaling would work. In future kernels, speedstep-centrino will be removed completely, so you can kinda see why this patch has not been applied to Gutsy.