I had several USB wifi-dongles before in my pc, but none of them delivered the speed what should be the maximum. I tested all of them on speedtest.net but every time the result was around just half of the speed of our connection ( we have 75mbit net, results were around 30-35mbit).

To compliment your high speed wireless modem router, TP-LINK have launched the Archer T4U, a wireless Dual Band USB adapter that supports both 5 and 2.4Ghz bands plus high speed USB 3.0 connectivity for additional performance.