I have a Router D-Link DIR 615 - Firmware Version 20.06, but the network is too slow, I did some testing LAN and ping it to the router, and it is absurd to sway and response time reaching 17ms, this network internal, I found it very strange, it was with the Firmware 20.04 I decided to upgrade and reset the factory settings to see if it would solve the problem, but still the same.
Here in the room have a Dlink 524 my ping test is fixed to 1.xx ms min with variations: min 0.912 max 1.281ms
Thank you all