@gtenorio
Are you using PPPoE?
Since version 2.6, pfSense will be able to transport
the entire WAN load over much more then one queue.
So if the CPU is sorted with much cores and/or threats
it can be a really good chance to get a fast as can WAN port / throughput.
If you are running or using PPPoE you will be nailed
to one CPU core and one queue! So if you now
having much more to do for the CPU, it can be
pointed to that circumstance told above
(more queues = more throughput = more CPU
load or tasks)
7 x 1Gbps down/100Mbps up fiber
1 x 50Mbps leased line fiber
And with that much WAN ports, the entire amount of queues can be short and fast increasing once more
again and also stress the CPU once more as I see it.