What type of connection is being made with the wireless device that's experiencing slow internet speeds? (ex: 802.11g, 802.11n, 802.11ac, etc.). What's Tx rate of the connection? Signal strength? Is it a 2.4Ghz or 5GHz connection? What type of ethernet cable is your Deco wired with? Have you tried changing any settings in the Deco app?

  @potatoes You ask very good quesetions - and I must admit I'm not tech saavy enough to really know how to answer. 

When looking at the app - it says my internet connection is IPv4 with Dynamic IP as the connection type.  I didn't find any information re; Tx rate.

The speed is set to auto switch between 2.4ghz and 5ghz.

There is a Cat5 cable going between the modem and the main deco. 

I haven't tried changing any settings since I don't know enough to know what to change. Afraid of screwing things up.

  @David-TP You mentioned the following: "2.4 GHz: 300 Mbps (802.11n)". Is 802.11n at 300Mbits on 5 GHz as well?

  @David-TP The issue I'm experiencing with my XE75 Pro is that I have an older MacBook Pro with 802.11n WiFi, and it connects on the 5GHz band and 40MHz channel at 300Mbits. It can download maximum at 210Mbits. On my old router from another brand, I was able to make a 400Mbit connection, and download at 270Mbits. My internet is 300/300. I'm guessing it might be some kind of a hardware issue/limitation, because I tried different settings suggested by support documentation, and nothing helped. All of my other newer devices work as they should.