Really Slow Wifi Speeds

[SweetDangos]

Ever since I moved into my new apartment I haven't been able to get my wifi signal to the same speeds as my old one. It slows down to a crawl when on the 2.4Ghz signal or flat out drops despite having full connection. My speed is 100Mbps/10Mbps. When I'm on the 5Ghz signal everythings as it should be but the second I connect anything to the 2.4 my speed on my laptop is 5Mbps down and about 300Kbps up if I'm lucky.. I've tried changing all the router channels to no luck and made sure the firmware is up to date.
ISP is comcast,
Router/Modem is the xfinity tc8305c bridged to my Linksys AC900.
Computer is HP15-bs015dx
This problem persists with my phone and all gaming consoles as well. Only workaround I've found is LAN cable or 5Ghz if my device allows it

 

[elbert]

There are 3 possibly causes bad microwave, draft jamming, or just to many neighbours with wifi in the area. About the only fix is directional antenna which can be done free using a soda can.
http://lifehacker.com/5839243/use-an-aluminum-can-as-a-wi-fi-extender

 

[kanewolf]

Since you have an AC router, the best choice may be a dual band (2.4 and 5Ghz) USB adapter and use the 5Ghz WIFI.