With an TP-Link Archer T4U USB3 wireless adapter I get the following on 5Ghz in a Windows 10 Home Powershell.
netsh wlan show interfaces, results in this:
There is 1 interface on the system:
Name : Wi-Fi
Description : TP-Link Wireless USB Adapter
GUID : ****
Physical address : ****
State : connected
SSID : WiFi-Gast
BSSID : ****
Network type : Infrastructure
Radio type : 802.11ac
Authentication : WPA2-Personal
Cipher : CCMP
Connection mode : Auto Connect
Channel : 44
Receive rate (Mbps) : 54
Transmit rate (Mbps) : 702
Signal : 100%
Profile : WiFi-Gast
Hosted network status : Not available
I have a similar Linux setup in the same room and the device log shows most of the receive packets in between 400Mbit and 800 Mbit.
I know the AP is setup properly because with my laptop's internal Intel WiFi Card the connection is properly, 780 Mbit, both Receive and Transmit.
I just installed the latest driver from TP-Link, but the driver version drops from 1030.11.503.2016 to 1030.2.731.2015. So I reversed that.
I forgot to say that the initial seconds/minutes after connecting, both speeds of the TP-Link WiFi are high. Than the receive drops to 54 Mbit and never goes higher. Whether it is wifi N / AC / 2.4 GHz or 5GHz, the receive speed drops to 54 Mbit.
I did a speed test with LANBench, between a Gigabit host as client and the TP-Link Archer T4U as server.
Results is a receive speed of ~190 Mbit and a received speed of only! 4 MBit.
I also did a Iperf3 speed test between a linux and windows client, with both a Archer T4U. Result was 90 Mbit.
EDIT: Now I found this thread, that discusses disabling QOS, which raised the speed to 156 MBit both ways. And it discusses a new driver that is not found otherwise.