I am trying to use a RB400 as my router. The problem is that once I installed the RB400 my internet speeds decreased to 0.14 Mbps. Upload speeds have not changed. I would post my current config however I don’t know how to get the file containing it.
I determined the decrease in speed was due to a bad network cable.once th 
e ethernet cable was replaced speeds went back to normal.
There could be any number of things causing that, like queues, or bad Ethernet links. From the command line, run “/export compact” or if it doesn’t support that “/export”. Then copy and paste the output here on the forum wrapped in code tags.
Some configuration is really limiting your internet.