First of all, thank you for the quick reply! :)
I've just found out the problem...depth of field...if I turn it off I'm steady on 60FPS on external view too...with depth of field on, no matter if simple or boke, (what's the difference???) my FPS goes very low...it's such a shame!!! That effects is my preferred one...makes all the scene such more realistic!
Cpu clock is 3,6 GHZ