A dilemma when mounting a new computer these days is: The system is an HD or a SSD? In the first there are options with plenty of space. In the second there is much more speed, but scarce space. Even with SSD 128GB or 256GB there is a risk of running out of space on the primary partition if you install many programs or if users have many documents.
An alternative to reduce the volume of data on the primary partition is to keep the folder Users on another partition. Thus, all user data, including those that are in folders Appdata can stay in a HD with more space, leaving only the SSD for system files and program files.
The problem is that there is no option for this time to install Windows. Then you need to follow some non-trivial steps to get the result. The advantage is that this needs to be done only once during the Windows installation.
Found esse excelente tutorial no Windows Eight Forums, so I will not reproduce the steps here, only indicate the link. I also did a PDF copy (User Profiles – Relocate to another Partition or Disk) apenas para fins de preservação, If ever the link exit air. Also saved the relocate.xml, it is more practical to put it on a flash drive and just make the necessary changes when you use it, instead of having to type anything.
Just a note: com a pasta Users non-standard location, Windows update 8 for Windows 8.1 does not work. You will need to do a clean install.