I've bought an Archer T4U V3 around 6 month ago to use on my PC together with an Archer C6 Router. It has been working just great for the first 4 or so month on the 5HZ band, but then the connection started to be unstable.
When I tried to ping an external server as a test it would drop(time out) 1-2% packets in 10 of pinging. I tried to switch to the 2.4HZ but insted of randomly timing out some packets would ping at 2000-3000 ms instead of the regular 20-30 ms.
I tried installing the the drivers for my model from the tp-link website, but it only made the situation worse. Now I can no longer connect to 5HZ band at all, the usb adapter just restarts when I try. I can sometimes connect to either my own 2.4HZ wifi in like 10 tries or an external xfinity public wifi, which is a little bit more stable but also resetarts the adapter sometimes.
I have a laptop on the same table that my PC and it has built in wifi that works perfectly fine with either 2.4 ot 5HZ and does not drop packets. I also tried using the adapter with my laptop and it shows the similar behaviour that I had on my PC before the driver update(periodically either losees packets or ping goes very high). Furthermore, I tried pinging the same servers directly from the router with the built in feature and the ping is perfectly fine with no lost packets.
Thus, I believe the problem is with the adapter/driver itself or maybe some settings I should tune and would really appreciate any suggestions.