So I had reset my wireless settings about a week ago and thought I had set everything back to the way it was. However, I was having horrid 2.4ghz speed issues. I mean horrid. Doing a speed test(speedtest.net) using my laptop and my phone(both had similar results), I was getting 500-900K download speeds(the graph looked extremely erratic too) standing right next to the router, while on the 5ghz I was getting 30+mbps download speed(aka. no issue). I could not figure out what it was that was causing the 2.4ghz issues. I tried a bunch of different channels and wasn't seeing any change. I had been trying the 20/40mhz or the 40mhz setting only. However, I decided to try the 20ghz only setting and my 2.4ghz speeds took off to about 15-20mbps download speeds. Now, when I first got the router(RT-AC66U literally when they first hit) and played around with the settings, I originally had it set on channel 6u and 40ghz and it was great up until recently(you can search my posts and see where I listed my settings). However now, when I set those settings, I get DIAL UP dowload type speeds(the 500-900k speeds). As I mentioned, I tried just about every channel on the 40ghz setting to no avail. Any ideas what is causing this? Is there something in the more recent firmwares(ASUS) that may be to blame? I have been running Merlin's builds but even tried some earlier builds, back to .48 Merlin builds and even ASUS builds but nothing changed. I'm wondering if a hard reset and reload of the firmware will help(not sure even how to do a hard reset with these).