Recently upgraded my ISP service to 300 Mbps down / 10 Mbps up. Running a web-based speed test from my ISP's server (WAN side) on a desktop PC wired to LAN port of my Asus RT-AC86U I typically reach 20% above provisioned ISP speeds with QoS off, but as soon as I enable any QoS features on the RT-AC86U, my download and upload speed test results drop significantly by roughly 50% to between 60 and 120 Mbps down / 6 to 9 Mbps up. The result are on the upper end (still...
RT-AC86U wired WAN-LAN throughput with/without QoS (stock fw)
RT-AC86U wired WAN-LAN throughput with/without QoS (stock fw)