I'd just like to support what cloudscapes is saying. I just tried the new version of Bart PE and after booting "windows" is using 17mb of commit charge (that's RAM + page file) and that's including the 8mb for Bart PE's menu system (which wouldn't be needed in a true Gaming OS).
A usual XP system is using around 150-200mb (more if you run continuous anti-virus proggies etc.) at boot. This kind of memory usage is not scalable thus it's overhead. No matter if you're running a AMD FX-60 or a Pentium III 500 you're going to be using that much memory. So while a 64mb xbox is rougly equivalent to a 256mb PC you can't apply the same ratio when you have 512 or 1gb of ram on the PC. If anything the xbox 360 (for instance) is going to be using a little more memory for its "gaming kernel" than the original xbox did.
My own installation of Windows XP is tweaked to the hilt and after boot it's using less than 100mb of commit charge (around 70mb of RAM).
A usual XP system is using around 150-200mb (more if you run continuous anti-virus proggies etc.) at boot. This kind of memory usage is not scalable thus it's overhead. No matter if you're running a AMD FX-60 or a Pentium III 500 you're going to be using that much memory. So while a 64mb xbox is rougly equivalent to a 256mb PC you can't apply the same ratio when you have 512 or 1gb of ram on the PC. If anything the xbox 360 (for instance) is going to be using a little more memory for its "gaming kernel" than the original xbox did.
My own installation of Windows XP is tweaked to the hilt and after boot it's using less than 100mb of commit charge (around 70mb of RAM).