The latest build(s) of SU 8 are "large address aware" but still 32 bit which means that now they can acces RAM "up to" 4 Gb on a 64 bit system - but no more. You can get the latest release here: http://support.google.com/sketchup/bin/answer.py?hl=en&answer=43176
💡 LightUp 7.1 | SketchUp's only real-time renderer that uses object-based rendering
Download Trial
L