Help Samsung Galaxy S4 Wi-Fi - Terrible Link Speed

[Recremac]

Hello! Having some very weird issues here with a hand-me-down GS4 here. I can connect to the wifi network with Good-Strong signal strength no problem, and immediately when I join I get a link speed of 72 mbps. After 30 seconds this quickly drops 5-6 mbps, and appears to stay that way. Coming right up close to the router boosts this up to 20 mbps and appears to work fine. The thing is though, I had the GS3 previously and never experienced such an issue from the same distance from the router. I have a BT Home Hub 5, just for reference.
I have tried switching channels on my routers settings, based on readings from the wifi analyzer app and have tried connecting to both the 2.4Ghz/5Ghz Variants of the hub. I have also turned off wifi power save with the *#0011# call. All to no effect.
Please help!!!
Thanks,
Mercer

 

[nu2andy]

http://thedroidguy.com/2014/01/4-samsung-galaxy-s4-wifi-internet-connection-problems-83593
I have 2 S4 i9505 GT phones. One is rooted and is running CM13 version 6.0.1 Marshmallow, and the WiFi connection shows 72Mps.
The other S4 is Standard and is running Jellybean Version 5.0.1 and the WiFi connection shows 65Mps!!! Both phones are extremely stable and are sitting side by side.
My Router is Fritz!Box Fon WLAN 7360.

http://forums.androidcentral.com/verizon-samsung-galaxy-s4/425226-wifi-low-signal-issue.html
http://www.zdnet.com/article/samsung-acknowledges-galaxy-s4-wi-fi-connection-problem/
This may be your answer.