I have just got a GT-KING but wifi speed is less then 1 Mps on 2.4G and/or 5G.
I got a speed of 60+ Mps on other devices that I have tested with the same conditions, same location same router and a internet line of 100Mps.
Yes, this is the same problem I see. The wifi is so slow, I cannot stream music on Pandora. It is very frustrating. Seems to be caused by a memory leak issue or similar, because I see a slight increase in speeds after reboot. After 1 week, the wifi is very slow again.
On my box I noticed that I must have at least 3 "lines" of signal to good throughput rate, but in same location with other device have about same performance. Try to refocus your router antenna and move your box in that position/orientation where you have max throughput/signal.
Users with slow WIFI speeds can try to connect other routers to see if the speed is normal. If the speed of other routers is normal, you can try to adjust your router 'channel'.:)