Archer C5400X slows down to half-speed after a few hours (wired)
I recently upgraded my internet from 300 Mbps down and 30 Mbps up to 600/100. I'm rebooting the router every day as I'm powering it down for the night. After the morning boot, I get full speed both ways, but after a few hours (can't tell how many exactly), the download speed gets cut in half. Upload speed remains unchanged.
I've installed the latest available firmware 1.1.2 Build 20191223 rel.73956(4555) both via the router's download and install option as well as manually from a file, just to be sure. Didn't help. Is there anything else I can check or try?
Some additional info:
- I'm talking about wired connection to my PC, not WiFi.
- The ISP is not throttling me because whenever this happens, I can just reboot the router and get the full speed... for some hours.
- I'm not using application-based QoS, I had my PC enabled on the device list with top priority set to "always".
- To check if the router is jst lowering the speed to my PC, but can handle 600 Mbps in total, I ran Ookla's SpeedTest on the PC and 3 mobile devices simultaneously and the total speed was also 300 Mbps so it behaves as if 300 Mbps was my max. speed.