@domagoj_zg 

Hi, The details are quite limited here so I will give some information for your reference:

1. Deco E4 has 2*fast Ethernet ports which are up to 100m/s if you have any wired devices connected to E4 directly.

2. If all the satellite units are wirelessly connected to each other, Due to the working pattern and protocol/regulation of Wi-Fi technology, the more wireless hops, the slower the speed would be.

So if you are capable to wire all the Deco units via Ethernet cables, it would improve the speed and instability a lot.

If not possible via cables, and you just bought the Mesh units, I suggest you could consider Deco M9 plus or Deco P9 if the whole house is under the same electric meter.

But it would be highly appreciated, you could draw a rough picture of the floor map about the distance and location of the Deco units, if possible, please also mark out where your internet modem is.

Thank you very much.