Microsoft revealed in the blog post that Windows 10 will take up as much as 6.6GB less space compared to Windows 8.1, will re-install faster and possibly be easier to rid of bloatware by using “Wimboot” disk compression to reduce system file and app sizes. Windows 10 will check system RAM and other hardware parameters before carry out the OS installation. You’ll create your own to backup and restore Windows 10 and apps on PCs and tablets (Windows phones already have this feature).
When you “refresh and reset” Windows 10, it’ll tap existing runtime system files, bringing your system to the same point you started at without the need to download all security fixes and updates on top of basic installation.
Microsoft said that
“we are also redesigning Windows’ refresh and reset functionalities to no longer use a separate recovery image (often preinstalled by manufacturers today) in order to bring Windows devices back to a pristine state.”
Blogging Windows [How Windows 10 achieves its compact footprint]
engadget [Windows 10 takes up less space and lets you easily kill bloatware]
BGR [Windows 10 will finally fix one of the biggest Windows annoyances]
The Register [Honey, I shrunk the Windows footprint]