I have Deco M9 Plus, gigabit internet, and I am getting gigabit on laptop in wired test similar to yours. Change Deco to Access Point mode and run your tests again.

@Alexandre. If i do that i loose the benefit of the deco router features and the m9 will simply turn into an independent access point. 

 

 

Marcel.... wrote

@Alexandre. If i do that i loose the benefit of the deco router features and the m9 will simply turn into an independent access point. 

 

@Marcel.... 

 

This is correct. The purpose of this is to verify everything is OK with Deco hardware and your home network wiring. In Access Point mode, Main Deco becomes not much more than pass-through for wired traffic. If in Access Point mode you couldn't get 300/30mbps with laptop wired to Main Deco, that would mean hardware issues or wiring problems.

 

The tests I did with Deco in AP mode using my M9 Plus prove M9 hardware is capable of handling gigabit traffic.

 

After you completed that test, you can change Deco back to Router mode. It is also possible that switching to AP and back to Router mode could reset whatever bandwidth throttling settings you have in Deco, but if not - then you can just review documentation on Deco Router configuration, with absolute confidence that what you have is not hardware issue or wiring issue, and solution to speed problem is somewhere in Deco Router configuration settings.