User having slowness when connecting vpn to remote office, plugged into a Mikrotik using sfp1 interface on a 100mbps connection. Speeds on site are fine, no packet loss to remote vpn point, but when connected rdp sessions are extremely slow.

Eventually I found a fix for this issue. I changed the wan interface mtu value on the Mikrotik to 1460. Since doing so the user vpn speed has drastically increased.