Getting Two-Digit MPBS download speeds, paying for 600!

Hey There, 

 

For a while now our home has been experiencing frustratingly low wireless internet speeds. We're paying for the "EXTREME PRO" internet package that is supposed to run at speeds up to 600MBPS. Recently, I've run speed tests in about every room in the house and on practically every type of device from iPhones to computers, to smart TV's and gaming consoles... the findings were quite interesting to say the least. 

 

We have one device that is operating on a wired connection, my wife's computer in the family room. That particular computer is running at over 560mbps. However, the highest speed I could capture wirelessly was at roughy 80mbps, on an iPhone, in the guest room (formerly my office) where the router/modem combo device is located. Other rooms I was getting speeds like 12.5mbps and 8.6mbps wirelessly.. no I'm not kidding. 

 

There's an obvious flaw in my system somewhere, and I cannot see it. My router is clearly capable of the desired speed, but is failing to produce it wirelessly. Has anyone found a solution to this issue or can offer me one? 

 

The Router/Modem is an Arris SURFboard SBG6900-AC

 

Thanks so much, 

Scott S