Why does not full internet connection to Pc arrive?

I have a problem on my PC come to a maximum of 4-5 mbit, although I have a 200k line. I've never had a 200k line on my pc but when i speedtest on my laptop i get full 200k. My Usb Stick program also shows the 200k arrive but speedtest shows something completely different. With dowloads I have only 4-5mbit. Do not know what to do probably someone can help

Connect the PC via Ethernet, then it's quiet.

First of all, Mbps and MBs are not the same.
Is your PC connected via WLAN or with a LAN cable?
And you should ideally have a download rate of about 25 MB / s.

Is bad if my pc is 2 rooms away

Wireless Internet access

You're right, you can cable of course, a maximum of 1 room.

Walls disturb your Wlan, if every room has at least one wall, there are 3 walls, because the speed is no wonder. So tear down walls, then there's a nice big loft-like room, or you'll drill holes in the walls and lay cables.