I can't speak for minimum requirements, but i run a 9-box in ZG atm utilizing the below PC:

i7-4790K
16 GB Ram
GTX 1070 Graphics

It handles it very well, main window is 50+ fps, all slaves are at min graphic setting and main window is set to 7 of 10 graphic settings. It will bog down some if i try to watch Netflix/Plex on the side. My setup includes three monitors as well with all windows master/slave on my main window.