ok after 7h 29 minutes prime95 without hard freeze or errors i guess i 've solved the probleme of mine...
no garantee that this will work for your rig but here is what i have done:
over voltage---> cpu gtls +14 mV (vor gtl 1 and 2 13 mV) afterwards i checked the vtt value and resetet it on auto (this was the old value but i reentered it anyway)
last but not least i entered the timings for my ram one frequency step under retail values (look @ cpuz for this)
i kept the higher voltage for my ram (1,8V cpuz said i should use 1,5V)
but be warned raising the gtls is @ your own risk