ty guys! , the only restraining factor seems my
X38-DQ6 (or... my inability to tweak it.. :P) as my first attempts to find a stable high fsb setting had poor results , partly due to my 4x1gb sticks. above ~415(5:6 - ram 498) starts asking for much vMCH in non linear "response" (1:1 setting is obviously much more demanding in terms of vMCH :S)