All posts are being helpful especially from bif and it is as he says if big air won't fit then h50 is an alternative, i stand by what he says. And bif i'm still torn as to what to get, i've re-measured and my god it'll be tight like a mil at best or maybe just touching and now i'm wondering if it will cause vibration/noise. Such a pain!! The mega would clear everything else like ram and other onboard heatsinks so that's a plus i suppose.