What I discovered was not to use Port 1 for anything other than POE on the RB450 There is something different about that port that in two different tower uses, is limiting BW.
Heres the scenario.
My towers are generally low BW use (always less than 10Mbit).
If i am feeding Tower A, and there is a Tower B "behind it", I keep both router's main WAN ports on the same "wire" or subnet. This allows me to keep one subnet just for WAN ports on a physical segment. Simple enough.
So, what we were doing was Bridging Ports 1, 2, 3 calling in WAN_Ext. and pluggin the BH TO the router into port 1, and the BH to Tower B (C also) from Tower A, into ports 2 and/or 3. Have done this consistently with 532s.
What I ran into was VERY slow BW across the WAN to Tower B, C etc, So, I eliminated Port 1 from the bridge and instantly solved the problem.
I then said, OK, lets just try and use Port 1 as the port we use to feed our 3Com 3300 managed switch at the tower. Moved those addresses to Port 1 and still slow acccess. Plugged my PC into Port 1 (backside of POE) directly and still slow access. Then I made the WAN_EXt bridge be 3, 4,5 and made the feed to our 3com switch be port 2. Plugged in directly into port 2 and instantly fast access. Moved back and forth to port 1 a couple times to verify the same results consitently.
Had this exact same scenario at a 2nd tower (both were 1 day old installations at existing towers). again, turning on or off FW rules and Queues made no difference on the problem.
Kind of unrelated issue on the same router(s). In trying to find things on this subject, I found Master/Slave Ports (for more like a true switch) and have now used those for my WAN_EXT ports. While for most traffic "passing by" my network, it doesnt make much difference, testing showed me able to pass 60Mbit through the "switch" type config vs. the bridged config.
But, the interesting part of this, was that Port 1 could NOT be used as the master port of the "Switch config", further showing that something is different on it.