KNOWN LIMITATIONS:
The processor performance state may not be restored to the maximum state if the CPU runs at 100 percent. This problem occurs if the computer is 100 percent busy when the power policy changes.

Does that mean my processor could be damaged permanently? And what do you think about that driver, should have I installed it or not?

Install it if you intend to use cool'n'quiet. If you like for your system to be silent when you're web-surfing, listening to music, etc. it could certainly help. Otherwise there's no need.