The link speed is 78Mbps? check the wireless environment firstly, adjust the antenna and upgrade the driver

Thank you for your answer. I confirm that the speed on the router is around 80Mbps. on other devices I can receive on 5GHz wireless around 78Mbps. I've tried moving the access point, adjust the antennas of rhe card behind the pc and update drivers with the latest available on the site but nothing ...

http://www.tp-link.com/us/download/Archer-T6E.html#Driver
Download and install the latest drivers from TP-Link

Already downloaded and installed the last driver but nothning change.
The strange thing is that last weekend I activated the 5GHZ Wireless network of the Dlink modem that provided me my ISP (which is a s**t) that is before the Archer C7 and that works perfectly at 78Mbps in down and 20Mbps in up (the max of my connection).
It seems strange that it works with different brands and not between TP-Link products of same series.

I tried another time to do some tests on the Archer C7 5GHz Network settings changing, instead Auto, the options Only 802.11, Channel width 80MHz and the channels 36 or 48 but nothing :(((

The router with my notebook and smartphone work ok sending 78/20
The receiveng card on PC with Dlink work receiving 78/20
The router with card don't work.... max 30-40/15 Mbps....