Yes that's right. I tried the proposed fix of nabbl from www.computerbase.de and disabled the "Enhanced Intel SpeedStep Technology of my Intel I7-2600 and disabled C1E, C3 and C6 messages for the operating system too.
My processor ran on 2,4 GHz in powersafe-mode before because NC doesn't use the full power of one single core. Now my CPU is running in turbo-boost mode and is runnung now on 3,9 GHz with a temperature around 65 - 75 °C.
The time that Plaza 1 in front of the medicar need to load all players was about more than 0,5 seconds. Now it's less that 0,2 to 0,1 seconds. The fps freeze is very short now.
An other example is Pepper Park 1 Club Veronique. While i ran to the door i get fps freezes for about 1 second and now less than 0,2 seconds.

I have a Nvidia GeForce 260 GTX and I thought that I need a better graphic card to get better performance. But the CPU settings helped a lot and other games like Battlefield 3 work better now

A nice and easy tool to see your cpu speed, ram speed and usage and anything else is CPU-Z. It's freeware and works on the most Intel cpu's: http://www.cpu-z.de/

Thanks for your help nabbl