intel microcode overclock issue

Hi

I'm having trouble overclocking my intel i7 6950x on ubuntu. I narrowed the problem to an apparent conflict between having the intel microcode from the repository installed. Without the package installed i have no problem with applying an all-core overclock to 4.3 GHz but OpenMP applications seem to crash when run with mpirun. With the microcode package installed, all overclock options revert to standard 1-core overclock of 4.0 GHz. Is there a way to fix this? Does a manual install of microcode package from intel allow overclcoking beyond standard BIOS settings?

Kind regards

Charles-Alexandre Mattelaer