I tested the FQ Codel for customer of mine and this time i used queue tree instead of simple queue. The CPU did not clock at 100% but somehow the thoughput gets congested to half of what you set in the max limit. I set the cap at 3000 Mbps for a customer and it capped the circuit to 1200-1300 Mbps and i started receiving complaints from the customer. I dont think its cut out for high capacity circuits.