intel_pstate and set frequency

Since with Ubuntu 14.10 intel_pstate is loaded by default and superseded the old acpi control, my old trick to reduce the frequency of CPU didn't work anymore so I couldn't cool down the processors while running some demanding software (and prevent overheating).

So bad.

Instead of disabling intel_pstate as suggested by some, I digged into the issue and found that

sudo cpupower frequency-set -u 1300MHz

works as expected (and indeed it doesn't block the frequency to a level but only sets an upper limit!).

So good!