@LanceJoseph They are compatible. The main difference is E4 has 100Mbps Ethernet ports, while M4 has gigabit Ethernet ports. If you plan to have Satellite Deco wirelessly connected to Main Deco M4,...

@Smats Deco M5 has gigabit Ethernet ports. I would recommend keeping M5s and have one of your M5 as Main Deco. Only if Main Deco M5 can't handle the load in Router mode it would make sense to look...

@omrid Connect laptop to the second Ethernet port of Main Deco and run speed test again. I would recommend running 3-4 speed tests back to back, with no interval between them. If last of these speed...

@Jonchill It is possible that some sort of WiFi signal interference had been introduced, such as new microwave, fridge or cordless phone. Also that interference might have been coming from your...

@tiboc I would recommend NOT to make Deco X50 Outdoor your new Main Deco. When you add it to Deco mesh, Deco app might even suggest to make X50 new Main Deco, you should decline that suggestion. With...

@tiboc Do you plan to place Deco X50 Outdoor outdoor, or you plan to keep it somewhere in the house? Also, do you run Deco mesh in Router mode or in Access Point mode?