Win8 only uses less than 30% of that 8GB with only some background processes running. Are you saying Unity was using up your RAM? Do you happen to have a browser with 50 tabs opened?
Yes. It was using around 5.5GB. So high was its usage that I had to download RAM Map so I could convert standby RAM to free RAM (the method Windows uses to free up standby RAM when required isn't perfect, apparently -- I actually ran out of free RAM entirely when downloading a particularly large file from Mega, and annoyingly I had to start it again as Firefox refused to address the fact that more RAM had been freed up [not much but enough to complete the download]).