10box on this setup possible?

[Origination]

I'm running 5 right now on this setup, and was wondering if it's possible to push more, up to 10, or what I would need to upgrade for it to be possible?

I'm running 5 on all lows settings, low resolutions and minimum render scales. 20fps on main and 10fps on the others.

i5 2500
16gb Ram
RX 580

I get about ~50-60 cpu usage when running around gathering and 11gb/16gb of ram usage.
When I was running 30 fps on the main and 20 on all of the extra boxes, I was getting some freezes that would last a second and would happen every 10-15 seconds or so so I downgraded the FPS even more.

Would it be possible to squeeze 10 boxes on this setup or what should I upgrade to be able to run 10 on similar settings?