Internet speed slows down over time?

Ap
7

When I turn the wlan on and off at the laptop, I have about 15 Mbps. After 5 minutes I'm under 2 Mbit / s. The router is not, which has already been reset.

Internet speed slows down over time
Pe

Download in the background? Others in the house which burden the line?

Ap

No both excluded

Pe

Could also be a broken network adapter. Do you have a WLAN stick at hand? Or n LAN cable?

Ap

Lan cable but not Wi-Fi stick

Pe

OK. Stick in, test, report

Ap

Have my at least 10 years old Wlan stick unpacked, which even creates the 16Mbit we have, now it's back to how it should

Pe

Then it is a defect of the adapter. If it works again then it's perfect