I currently use a Dell Xps 13 with a killer 1535 network adaptor. My internet speed dropped suddenly after returning from a vacation. The only thing that changed was that I downloaded some games from Steam to pass the time on the trip there and back. I checked and I have the latest driver version for the network adaptor.
Edited for clarity
Edited by Hugh_Mungus, 14 July 2017 - 12:48 PM.