TP-Link TL-WDR4300 and Intel AC8265. RX = 300, TX = 150. Why?

[lleachii]

@loser

So, I should get 300Mbps. The thing is, even though in the connection properties the link speed is displayed as 300, in the web administration page, its RX is 300 and TX is 150 when copying a file (the values go down when doing nothing).

I think you're referring to the PHY width or channel bandwidth (20, 40 or 80 MHz), not the actual speed...this bandwidth will go down when there's no traffic. You must perform a Speedtest or other high-traffic testing while measuring this.

@loser

Consequently I get only 12.5MB/s file copy speed.

This seems somewhat normal...That's approx 100 Mbps...not bad, depending on the SoC and other processes running (i.e. LuCI)....but...

@loser

What settings should I change to make the TX of my laptop 300?

Have you tried enabling Software and/or Hardware flow offloading?