I have a RB850Gx2 and one of my ports is limiting TX to 2Mbps. I can't figure out why.

This model does NOT allow bandwidth limits tx/rx per port (that I can see)
There are no queues setup

What is causing the speed cap? Is there somewhere else that speed can be capped?

I've spent an hour and can't find the cause. I carried my config over from an old RB450 - wondering if that matters?

Why do you think the port is limited? What is the CPU load while testing? Could it be cable related (do you see a lot of CRC errors)?

I did a speed test (to internet) from each port, and all run 36Mbps download with a slope upwards. Port 5 is 2 Mbps download with a flat graph (i.e. capped)