Question Cannot disable turbo boost feature on my I5-750


Aug 25, 2019
I am overclocking my (rather old) I5-750 with motherboard Asus P7P55D-LE
For some reason I cannot turn off the Turbo boost feature
I select Turbo boost - disabled, from the BIOS
I put BLCK at 170 and CPU multiplier at 21 (which is the max possible multiplier) and increase the relevant voltages
With high multipliers like 21, the Turbo boost feature disappears from the menu (and presumably is disabled because of the high multiplier).
  • When I run tests using the 4 cores, the CPU frequency stays constant around 3570 MHz - as expected
  • When the system is idle, the CPU frequency goes down around 1500 MHz - as expected
  • However when only 1 core is under heavy load, the Turbo boost feature kicks in for some reason and increases the multiplier to 24 , putting the CPU frequency above 4000 MHz (which is not stable anymore).
If the CPU multiplier is at 20 or lower, the above effect does not happen and the max speed is 3400 MHz, no matter the number of cores under load...

Do you have any idea how to disable Turbo boost completely without disabling the possibility of the CPU to underclock when idle?

Thanks in advance
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