I have two PC's both with an A6210 card and one runs perfectly, averaging 20ms to google servers on ping. The otehr card fluctuated between 210 and 450, sometimes getting up to 2100. The connection often drops out altogether.
You can try disabling QoS in Anti-Bufferbloats options to see if that helps. Would suggest replacing all the ethernet cables connected to modem/router as well to ensure its not those either.
