Goodcloud network speed slow

I`m using the Goodcloud VPN since 2 years (3 locations in Europe) with 2 x GL-AR750S and 1 x GL-AR750S without any major problems. The only issue I have is the network speed, it only 30Mbit/s, although the upload speed in one location is 40 Mbit/s (DSL location) and at the other site is 500 Mbits/s (fiber location). Is this a network limit or does anyone have an idea what the issue could be. Many thanks
Best regards

Do you mean Site-2-Site?

Which location is your main node?

The main node is a fiber site with min 500Mbits WAN speed.
Both other sites are DSL with 100/40Mits upload /download max speed.

First of all, the maximum speed between two sites is the lowest uplink bandwidth of one of the two sites. The download of one site is the upload of another site.

Then Internet providers in Europe to Spain are very poorly connected to German Internet providers. This is due to the topology of the Internet in Western Europe. And since bandwidth costs money across borders, you can talk to your ISP to see if they will give you a guaranteed bandwidth to the other location. this is what companies do when they need that bandwidth.

In my experience, GLINET S2S connections are usually as fast as the hardware of the device allows. See here the Wireguard values of the models: VPN Router & Services Ratgeber › Alles was Du wissen musst!

The 750 models can handle up to 45,000 kbit/s (up and down together), so they should be able to handle 35,000+. The rest, i.e. if you lack more speed is probably due to the maximum upload of the Internet access via the peering between your Internet providers.

The performance of the Internet lines themselves may be good, but as said the lowest upload limits all connections automatically and the upload is calculated from site A to site B and not only from the site to the Internet.

I understand, thanks. Does this mean follwoing, if:
-the main node has internet speed 500Mbits and site1 has internet sped of100Mbits the max VPN speed between the main node and site 1 could be 100bits

-and site 2 has an internet speed of 50Mbits the the max speed between the main node and site 2 could be max 50Mbits