I bought last week a USB3 wireless adapter (Archer T9UH EU v2) and since then I'm having issues with the slow speeds.

I'm using the device with a desktop PC - i5 quad core, 15Gb Ram, SSD drive, Windows 10 Pro with all the updates applied.

My router is a ASUS RT AC-66u with the latest Merlin firmware.

The problem I'm facing are verry slow speeds an average of 160Mbps with the router in the same room at 3m away from the wifi adapter.

On the first time use windows detected the adapter and installed the latest driver. Seeing the slow speeds I downloaded the one from the tp-link site but after installing it I get error 10 in device manager. Same happens with older drivers. The only workarround was to restore windows to an erlier state.

After a few more tests, using USB Device Tree Viewer I noticed that the device is seen as a USB 2 device despite the USB ports are USB3.

I've tested the issue on another device and had same results. Device operating at USB2 speeds and the connection speed is very low.

I know that the device speeds will not be the ones advertised but I've expected at least half considering that my connection is 1Gbps and using my note 9 from the same location as the adapter I get 400-500 Mbps on average. My wired connection speed is at 800-900 Mbps.

My USB3 ports work ok. I have tested them with other USB3 devices includeing an old non AC Tenda wireless adapter.

As I know the chipset for the archer adapter is a Realtek 8814AU I even tried

I would like to know if there is anything else I could try before I send it back.