Minimum CPU requirement for FreeNAS 11

I want to build a cost effective NAS using FreeNAS 11 version for my small office having 25 concurrent users with 6TB usable space & hot swap-able hard drive. Can anyone suggest what specific CPU & motherboard should I consider & whether having SATA DOM / Flash is mandatory for OS?
Although minimum hardware is mentioned in documentation I want to know the exact CPU with optimal clock speed; for example Core i3-7th Gen / i5-7th Gen / i7-7th Gen etc.

Thank you!!