Well it's a new day and more strangeness... btw thanks for the input guys!

Last night, I just shut it off when I couldn't get the thing to post while overclocked... then went to sleep.

Today I tried it with exact same settings (and each stick of ram seperately including the single good crucial) and they all work stable in memtest for 10 minutes. This leads me to believe my motherboard is giving me this problem and it could well be heat related.

You guys reckon my northbridge could be overheating ? I could easily connect a block I have to it using my second water-cooling loop if that turns out to be the case.