Hello all!

Yesterday I purchased a Deco M4 AC1200 (pair). I have a 1Gpbs(down)/500Mbps(up) Internet connection. It's a two three bedrooms house.
I have installed my main Deco on the hallway (next to my Fritzbox 7530AX modem/router).

The other deco, is connected to the mesh network wirelessly and is on my office which is in the living room.

The two decos are within a range of 8 meters or so, with no walls between them.

My PC is connected with ethernet to the second deco (office).

My problem:
If I try to to do speedtest from my PC, I get about 400-500Mpbs down and about 350-430 up. I get the same speeds with my laptop from the same distance of the decos (also using it from my office). So the setup is two devices on the same room and on the same office, one connected wirelessly and one wired, and both of them get the same speeds. If I connect my laptop to my main Deco with ethernet, I get about 950Mpbs down and 500Mpbs up, which is the desired speed. So the connectivity to the Internet is working at promised (by the ISP) speeds.

Troubleshooting:
I have tried to use only 2.4, then only the 5Gz bands. I have tried using both WiFis (on Decos and on Fritzbox) with same and with different SSIDs. I have tried to use 2.4 on Fritzbox and 5 and Decos and vise versa. I have also tried Router mode and Access Point mode. On router mode, I have tried with QoS enabled just for my device and totally disabled. Also tried switching the main Deco as I read in one post in the forum. I have tried with another speedport modem/router provided by my ISP that I have as backup, with enabled and with disabled WiFi on it also (same testing with Fritzbox).

Current setup:
The decos are placed as described, are using both bands and are in AP mode. My office deco is connected wirelessly with my Main Deco and also has my PC connected to it (office deco) via ethernet. I have totally disabled WiFi on my Fritzbox. Last but not least, ALL ethernet cables are brand new, Cat 6a category. Both decos have the latest firmware and also fritzbox has it's own latest.

Possible conclusion:

I don't think that modem/router has an issue. I experienced the same issues on both routers. Via ethernet on router and/or on main deco, speeds are as expected.

Any ideas? I can't think of anything else to test right now..

Thanks in advance.