Slate AX/Flint 2 Really Slow With Wireguard Site-to-Site VPN

[a23]

I have a Flint 2 & Slate AX Router.

my ISP is Comporium fiber; general speeds are download around 400-500 Mbps and Upload around 150 - 300 Mbps.

Configured Flint 2 as Wireguard Server, Enabled Dynamic DNS, Port # 51820.

Generated the Wireguard Client from my Wireguard Server (Flint 2), and uploaded it to Slate AX router Slate AX for Site-to-Site VPN.

Wireguard Client is working as expected and showing my home IP, but the download speed is around 15-20 MBPS, which is very slow. I know that Wireguard Site-to-Site VPN download speed is based on home internet upload speed, but my upload speed at home is around 150-300 Mbps.

What can I do to improve Wireguard site-to-site VPN Speed?

[admon]

Mostly by reducing MTU on both sides until the speed is great again. This is a really annoying task which will involve much time spending and testing - unfortunately

[a23]

@admon

Mostly by reducing MTU on both sides

admon, thanks for your reply.

just found the MTU option on the VPN dashboard page, trying to play with it and will update if any change. is that the only debugging option or is there any other setting I need to do on the Flint 2.

[a23]

after changing the MTU to 1380 on Wireguard Server/Flint 2, my download speed issue on Wireguard Site to Site VPN Client is resolved.

Now my download & upload speed is close to 150 Mbps.