You need to go into the motherboard BIOS and disable C1E, all C-states and Speedstep (EIST). Unfortunately, for p55 and h55 and h57 motherboards, the energy saving features need to be disabled because they make intel SSDs slow down quite a bit. Maybe Intel will fix this one day!
Some people said turning off VT also improved speed a bit but I didn't see any benefit in benchmarks.
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