So, as the title says - I'm experiencing slow LAN to Internet performance between a HAP AC2 router and a RB260GS switch.
My current setup is two different computers (1 Ubuntu Server and 1 windows Desktop PC) connected to the RB260GS switch, which is connected to the HAP AC2 router, which in turn is connected to my ISPs modem.
After a reboot of either the RB260GS or the HAP AC2 I can do a speedtest from either of the two computers connected to the RB260GS to https://www.speedtest.net/ and get my ISPs advertised speed (~300Mbps download/~100Mbps upload). But, after a while I only get (~100Mbps download/~100Mbps upload) - and I can't figure out why.
Troubleshooting so far:
I've checked that the HAP AC2 is not under any heavy load - neither CPU, RAM or otherwise. I've had a laptop connected directly to the HAP AC2 and tried a speedtest while the computers behind the RB260GS where experiencing the slow speed (~100Mbps download/~100Mbps upload), and the laptop directly connected to the HAP AC2 got the "correct speed" (~300Mbps download/~100Mbps upload). So, my thinking is that this is somehow an issue between the HAP AC2 and the RB260GS. After a reboot the speed is back to the "correct speed" - but after some time (between an hour and several hours) the speed just drops to ~100Mbps download/~100Mbps upload.
Any help, ideas or explanations would be appreciated.