I have a TP-Link WDR4300, with the latest 1.8 firmware.
I was trying out a speedtest, and comparing it to the DSLReports test. My speed started going down, first to about half, at which point I tried disabling QoS. Doing that, the speeds were normal (along with the normal lousy bufferbloat score). I tried a few times with enabling/disabling QoS, and sometimes just upload or download, and the speeds went down to about 5% of my max.
I couldn't see any obvious problems, and tried resetting the router and even my computer. Finally, it occurred to me to check the upload and download speeds, and they had somehow got set to very low numbers.
I hadn't changed any settings, just enable/disable checkboxes, and I only had one browser window open to the router. Has anyone else had problems like this? If this is a somewhat common problem, then is there anything I can do to prevent it, or should I just keep checking it periodically?
One other thing changed itself: the ACC ping target IP address reset itself from my OpenDNS setting to the original ISP setting, although it still had the checkbox checked for "use non-standard ping target."