I'm a little behind on the thread so one by one.
We have had three UEs on at once casually surfing with no issue. Samsung S7, Moto 4G, and HUAWEI 593-22s.
Our gigabyte order round 1 was for intel i7 5775 cpus. There is a known bug with that CPU and the 3.19 kernel. End result, they kernel panic randomly and reboot. Super annoying. We've actually seen with with the 4.7.2 kernel too. So.. maybe they just suck.
We ordered the same machine with i7 6500 and so far it has been more stable.
We have found i7 with 8GB of ram has been sufficient for us so far. Including 10mhz operation. Though some UEs do better than others at 10mhz.
We have been patching our master branch EPC with key commits from Anoop on the fixed-broadband branch. His base was really old so we aren't having great luck using the branch as is. He is working on merging with something more recent, but in the interim, we are cherry picking.
We are shooting for stability where a UE can join and rejoin over and over without cratering any processes, mainly MME. I think once Anoop has finished his merge mission it will be a real solid EPC branch... whether it's master or develop or something else.
That's where we are.