Although Windows 7 scored a little better in most test,
Windows 8 and 8.1 had smoother interface, loaded
programs faster and booted faster. They also used less
RAM and HDD space.
In games the three perform almost the same with the later two maintaining a more stable fps without noticeable drops.
All the tests were ran on the same machine with the
latest updates and the same video driver – AMD Catalyst 14.4
CPU: Intel Xeon 1231v3 @3.6GHz