@corok 

corok wrote

I recently bought a brand new TXE5100UH, a 70 dollar USB-plug in adapter since I needed one quick and couldn't wait for a PCI WiFi expansion. I didn't expect a whole lot, but the speeds are downright terrible! I have it plugged in to USB 3.0, on newest drivers, set to prefer 5Ghz and in the best spot I can get it and it barely breaches 15Mbps. I am on a 1Gbps plan and my S23 reaches 500-600 Mbps in the exact same location as the antenna

What is the S3? A laptop?

More info needed on the device you plugged it into.

What was it using before? If it has an internal Wireless card/adpater, have you DISABLED it or REMOVED it?

I assume you used the same NETWORK SSID before. Have you FORGOTTEN that SSID name? Could be part of the problem.

Have you tried setting it to the 2.4Ghz band, and if you did or do that, what speed do you get?