[ajg1977]

When I installed Windows 8 a few weeks ago, the 64-bit install was about 20GB so where the hell is the other 21GB going?

Is the recovery partition literally a mirror image of the default install? That sounds ridiculous because the thing is basically a computer so could have a USB-restore, but I don't see how they get to 40GB+ otherwise.

<facetious>21GB of trials and time-limited software? </facetious>

[dangrossman]

Plausible: 20GB for Windows, 10GB for recovery, 4GB for the hibernation file (has to match RAM size), leaving 6GB for the swap file, system restore points and preinstalled software.

[cma]

Seems like they could have something like a (but a little more nuanced than) union-FS for the primary partition joining it with the recovery partition. Only updated files would need to take space on the primary partition, untouched files would be sourced from the recovery partition. To restore you just wipe the primary. Of course, there is an entire blog written about how sensible ideas like that are completely impossible: http://blogs.msdn.com/b/oldnewthing/