I have a 1Gbps optic fibre internet connection, using a Huwai modem. The main Deco M9 is connected to the modem and functioning in router mode. Another Deco M9 is connected directly through a CAT6 ethernet cable, and the third one is connected using WiFi.
When I run the speed test on Deco app, I get up to 920Mbps of download speed, so everything is fine. When I'm connected through wifi to the main Deco M9, I get speeds of around 400-600Mbps, so it's perfectly fine. If I'm connected to the third Deco (which is linked through Wifi), speed drops substantially, but that's to be expected, I guess.
What is really puzzling me is that the maximum speed I can get from the second Deco M9, which is connected using the ethernet overhaul using CAT6 cables, is 92-96Mbps. QOS is set to standard and there are no priority rules. I checked the cables, they all say CAT6.
What could be the problem? Firmware is the latest.
Thank you so much for your help.