Why is my Htc Desire Eye so SLOW on wifi?

[AC Question]

On my Desire Eye the wifi is 40mbps and 5 upload when I'm right next to the router but if I walk literally 10 feet away, it goes all the down to like 4mbps download and like 1 mbps upload. When I go upstairs to my bedroom, the speedtests are so slow that it just fluctuates between 0.00mbps and 0.1mbps. Why is this happening?? It's not a wifi problem because when using my phone right next to the router the speeds are good. So this has to be a phone problem. Does anyone else with a Desire Eye have this problem? How do I solve this?

 

[Rukbat]

It sounds as if the wifi antenna inside the phone isn't connected, or it's broken (or the wire is broken).