TP-LINK TL-WDN4800 low Signal/noise, Slow unstable connection

Hello tonymac community,

many thanks first of all for all the great guides! I managed to get my system running 2 weeks ago with Sierra. The installation went pretty quickly and flawlessly and everything seems to be working fine. The only problem i'm having is the wifi connection.

I posted in an older thread on this topic, but since I don't know if I am having the exact same connection problem i am reposting now and hoping for help.

I've tried both PCI slots and also changing the router...

TP-LINK TL-WDN4800 low Signal/noise, Slow unstable connection