Plus more if you disable virtual memory, remove the recovery partition, disable system restore etc and run a disk cleanup. Figures from when I owned one:
Used Space/Ram used:
-17.7GB / 1.2GB (First boot after a fresh restart and left for a few minutes)
-12.9GB / 1.0GB (Hibernation, Virtual mem, Sys retore, encryption, all off)
-13.0GB / 1.3GB (All 73 updates installed along with a few apps, Office removed, temp folders emptied)
-12.9GB / 1.3GB (After Disk clean-up)
-12.9GB / 1.0GB (Various services disabled)