@PaulWilson 

If you go into the Deco app and select one of the connected phones on the device list do you see a option for high priority, if so enable that and test again.

@Tony  thanks for the suggestion. I just tried that but it did not make any difference. One thing that did help was locating the Deco higher up. I am limited with how high I can put it, but even just on a low coffee table seems to have helped a bit. Still nowhere near as fast. Still only getting 15Mbps compared to 80 on my laptop.