I have Deco M9 for years. Fairly stable almost always. Maybe did a complete reset once. And every so many months a restart.

I reset all my Deco nodes to factory settings and did complete reinstall/configuration of network.

Did network scan or wifi interference. It did optimization. (And did it again after speed went down again: no improvement needed, was already optimized).

Configured restart every night and automatic update. All nodes same firmware.

Tested my cable up to the Deco main node: 400+ Mbps. That is always stable.

Upload is most of the time pretty stable around 50Mbps. Not as instable as download.

All nodes connected with (fast) cables.

 

Advanced settings: (sorry have to translate from Dutch)

"Operationsmodus"(Bewerkingsmodus): wifi router

Static routing: ... looks like default or so

IPTV/FLAN: off

Clone MAC: off

DDNS: Off

LAN IP: ...

DHCP sErver: ...

Address reservation: ...

Fast roaming: on

Beamforming: on

NAT forwarding

> port forwarding: ...

> SIP ALG: off

> UPNP: off

 

 

Download speed is fluctuating. Sometimes down to even below 1Mpbs then up to 400+ again.

Sometimes restart works, sometimes it doesn't.

Drives me nuts ....

 

Read somewhere to set dns to 8888 ... That would be via Internetconnection > IPv4 > Internetsettings > ...   

>  Currently that is on Dynamic IP..

> For IPv6 also dynamic

 

Today, after very low speeds, just unplugged cable from modem to test speed directly (was great), then plugged back in to Deco and then wifi speed was up to around 400 again.

Is now stable for last 30mins or so. Will check again ...