Its Win8 64bit, been a proud 32bitter (minus win server 2012) until last month when I needed to use After Effects. I was just worried I would have to format and do everything again although I have to admit the super speedy full reinstall / full format in Win8 is quite amazing. What wasn't amazing was NVidia gfx update being a pain in the ass with shadowplay or wtf its called but I got that sorted too.
What is interesting is on my other mobo it said I had up to 9.2GB of RAM spare and now it says 9.8GB :/
The one thing I really hate is overclocking seems to be on by default. Asus has some nice OC features but I wish there was a way to simply opt out like literally and on / off option as it makes very little difference to me. CPU barely moves past 5% and even rendering massive scenes in Blender it doesn't even go past 40%, I cant really see any benefit for me to OC but it somewhat sneakily has it on by default
Anyway thanks for the replies