I purchased an RB1100AH earlier in the year as a backup for my production router, and RB1100, which was running 4.3 software. Yesterday, I swapped out the older unit, with the RB1100AH with the latest, greatest 6.4 software.
There appeared to be some issues with my small WISP, which motivated me to make the upgrade. It turned out that my two DNS servers (SUN Netras) were blasting as much as their little 10Mbps NIC's could handle. I'm assuming they were in some what hacked and being used for nefarios purposes. It was very easy to figure out with the new WebFig UI, as it showed me in real time the traffic rates.
What also helped me figure out there was a problem, was that the RB1100AH kept resetting. Literally every 1-2 minutes. Once I figured that out, I was able to disconnect both servers - yeah for Google DNS - less power consumption for my remote site. Now, now longer at the remote site, I've noticed that my VPN still resets every 10-20 minutes; I believe its associated with the RB1100AH resetting.
My observation with the DNS server initiated events, was that high traffic was associated with the resets. Similar traffic is starting to form as normal operation (20-45Mbps) which I gather is tied to the resetting.