World of Warcraft, New build question

[fatgump]

I am new to pfSense and was using a AMD 965 with 4 gig of ram as a test for a couple months. I liked it and built a new lower power system:

Supermicro Atom C2758 A1SRI-2758F-O
Kingston 16 gig ecc memory
Intel 730 SERIES 2.5-Inch 240 GB
Cooler Master Elite 130

The pakages I am running are darkstat, openvpn-client-export, pfBlockerNG, squid, squidGuard.

ISP 300Mbit/30Mbit connection

1 LAN (nic) connected to a Linksys 8 port gigabit switch that connects to 3 PCs (one for gaming) and a NAS.
2 LAN connected to Netgear R8000 that connects (WIFI) to 2 gaming PCs, 2 Fire Sticks, 4 phones, Direct Tv and a NAS
3 LAN connected to a Netgear WNDR3700 that connects (WIFI) to a XBOX One and PS4

Now for my question.

My Son wanted to try World of Warcraft so he signed up and started to download the game on LAN 1 (wired) and the pfSense box hit 80% CPU usage  I have never seen this system go over 20% CPU usage while testing with downloads and lan speed tests on multiple lans, is this a set up issue or does Blizzard do something different?

[asm]

Blizzard goes for DD and P2P

[W4RH34D]

They use P2P - and yes it can "destroy" your cpu if you're using proxy and anti virus.
I only have 150mb down and it was only saturating 90mb at it would shoot my cpu to 100%.  Once I turned of the AV (which I assumed was only scanning port 80 and 443) the cpu went back down to nearly nothing.  However, I have very bad nics which are being replaced today.
Bad nics can destroy your cpu when you're doing high traffic over a ton of simultaneous connections.
You should only experience this when downloading the game not during gameplay.
Intel(R) Core(TM)2 CPU 4300 @ 1.80GHz