@Tony What about 80-80 mhz? Could you please read this C3150v2 MU-MIMO Wave 2? C3150v2 was/is still being sold as a wave2 router. Seems to be an issue relating to a firmware not released yet, since...

There was a time when TP Link routers used to work right out of the box, without constant reboots, resets and stuff... Maybe Tp-Link should start listening its customers and act accordingly. As for...

Under "Advanced/QoS/Application Priority" choose Standard and under "Advanced/QoS/Device Priority" set everything to Priority disabled. Usually, after a restart the speed should return to normal. Is...

@Brother_Bluto disable QoS and try a speedtest from a wired client. Enabling QoS 'sometimes' cuts the bandwidth in half (bug?).