Internet connection speed dropping as soon as AOE 2 DE or HD is open

Hi All
I was playing AOE2 DE smoothly till recently when I relocated to a new place. I have 2.4GHz single band router with 50mbps speed ( when I check internet speed test). But as soon as I turn on the game, the speed comes down to <3mbps. When I close the application, the speed goes back up.

As a result of such low speed, most of my games end in server connection issues. I tried playing AOE 2 HD as well and there is a similar issue. I tried turning off ’ Allow the computer to turn this device off ’ option in the device manager for my adapter as well, but there is no difference. Any idea why this is happening?