OK Iv seem to fix my own ploblem. I am now able to run crossfire with 2 4770 and overclock my cpu from 2,5 to 3,0ghz.
The solution was to set my bios in default settings, this made the second 4770 able in windows. The second step was to overclock my cpu via the multiplers and not with bus speed. Before I ran the overclock cpu with a bus speed of 240 = 3.0 ghz.
Now I change the multiplier to 15.5x. This gives also 3.0 ghz. This is by far the best overclocking board I v ever had.