Thanks for the help! I tested to lower the CPU to 7X and then I could run 540FSB (1080 memory) but not more.
I guess my 1066MHz memory does not work at higher speed. Maybe a volt increasement to 2.2V would help...

But could my E8600 be defective? It does not respond better to a volt increasement. Higher then 1.5V is a no no!

Still 540x10 or 540x9.5 or 540x9 would be better then my 7x now...