I'm currently on a Linux based OS (Ubuntu 12.04), and was wondering how I would fair playing Minecraft in Win8 RC or Release Preview I guess its being called, with just 1GB of ram. My system idles between 150-210MB (pending Desktop Enviroment I'm using), and I can play minecraft (with render distance on tiny, but still).

It seems it can be done! With Optifine (in my case the Multi-core version) and most if not all settings turn down to minimal it is playable in Win 8 with 1GB of ram. Although you'll want to KO the extra unneed processes, and turn theme stuff off/ to minimal with windows as well.