I am so sorry to hear that Dieter, this is really terrible.
But I can assure you your English is fine. 

I also think your problem is somewhere else. You mentioned it yourself. and I
think Alex Deucher did as well, that your P-States are not changing.

I have two different screens. One HP ZR2440W connected via DVI and a Dell
U2412M connected via Displayport. Both run at 59.95Hz@1920x1200