Wireguard server issue

This is somewhat expected, actually. Two reasons I can think of:

  • [major] When you are running a speed test to a server on the internet, you will be limited by the slower of your upload/download speeds from the ISP.
    • if you were running the test while behind the router (i.e. directly connected to its LAN), the download and upload tests would usually be representative of your connection (assuming everything is working well and no critical bottlenecks exist). In those cases, your traffic will be primarily one-way (except for the acks).
    • However, when you are connected from a remote location to the router via a tunnel, the speed tests actually use both upload and download simultaneously.
    • Specifically, your computer/phone/tablet requests a speed test. That request goes through the tunnel and emerges from the distant VPN endpoint. From there, it goes out to the speed test site. The speed test begins -- let's say the download portion -- and the site sends a stream of data to your router. The router must then turn the data around and send it back out the tunnel to your computer/phone/tablet which is the actual endpoint of the speed test. So the speed test data stream comes in as a download, but has to go out (encapsulated within the tunnel) as an upload to send it to the test endpoint. Therefore, the download test is approximately limited by the upload capacity of your connection and vice versa (whichever is lower is the one that dominates).
  • [minor] While Wireguard is actually very fast and lightweight in terms of a VPN technology, it does require CPU resources for encryption. This means that the load increases on the processor, and in more extreme cases, the capabilities/power of the CPU can have an impact on the bandwidth.

Hello,
thank you for the explanation, seems its bit complicated...

Well okay the openwrt router connection is ~ 300/50;
the wireguard client connection is 60/15

thx