I will jump into this conversation as it also affects my current router and network speed. At the moment I have a TP-Link C2600 (IPQ8064) running OpenWRT 18.06.5.
My ISP recently upgraded the bandwidth speed from 100 to 200 mbit download/upload. If I have SQM enabled with the recommended scheduler (cake/piece_of_cake) and testing it with speedtest it is limited to 100mbit. If SQM is disabled I can get around 170-180mbit/s.
And I am not sure what could be the cause. Would this mean, as suggested in the 2nd post that for QoS/SQM to work I need at least a x86-64 router because of the per-packet processing ?
At the moment I am looking at Mikrotik offerings (Such as hAP ac2), but I use WireGuard which is not available there.
EDIT: My question is - What device would be sufficient for SQM/QoS to sustain 200 mbit network speed ?