Depends on what your doing?... Routing? or Bridged? or Switch Chip?... I use mine at my house for testing and as my main home router... With minimal rules etc I am getting easily 100 Mbps NAT.... its the same proc as the RB2011.
2 ethernet are doing a loadbalancing of 2 fiber 100/10, 4 ethernet are configured as LACP with a NAS and the servers of the company conected to it doing backups.
Nobody said me nothing but... I dont kmow where is the limit...!