Problems with the load of the Wi-Fi network. How to decide?

Question

WiFi

When the network is under load (watching a video on youtube, downloading a file, etc.), the Internet on the laptop starts to work slowly. The speed drops to ~60 kb/sec. Moreover, this persists for some time, even if you stop watching the video or downloading the file.
Did a downgrade of the Wi-Fi drivers. Helped for 3 weeks, then the problem returned.
On a new clean system, everything is the same.
intel centrino wireless n-130 adapter.
The D-link dir 300 router is used.
On a computer connected to the router with a cable, the problem is not observed.
I tried changing the channel.
upd
Checked on another laptop
The problem is not observed

Answer 1

Change the channel, but if there are a lot of routers around, they occupy all channels and thereby create interference, repetitions and errors during transmission to the radio, especially under heavy load, then this issue can only be solved by laying a wire or switching to 5Ghz.

Answer 2

There is another solution, but it will be for more money and not a router, but an AP.
As mentioned above - if the problem is interference, you can take such a thing = for the house for the eyes.
But I emphasize that this is not a router, this is a full-fledged AR that can suppress interference

Answer 3

Kind.
If it's not the PC and "noisy", then, as an option, just try replacing dlink. Maybe he has problems with wifi.