VPN speed using Raspberry Pi 3B+

[Radiofreak1041]

Hi,

I am running a SoftEther VPN Server version 4.34 Build 9745 on my Raspberry Pi 3B+.
The uplink and downlink speeds of my server-side network are 200/200 Mbps. However, on my client side network with a 500/40 Mbps up/downlink, the maximum download speed I get when connected to my VPN server is around 50 Mbps. I was expecting something closer to 150 Mbps.
Can someone explain to me why this happens? Is this a processing power limitation on my RPi (I'm not seeing excessive load in my CPU usage graph) or can this speed be improved by tweaking some settings?

Thanks a lot!

[eddiewu]

What is your speed test server? The default server is in Japan.

[Radiofreak1041]

I have not configured a specific test server. I mainly use the VPN for remote desktop access and SMB file transfer, which reports a 50Mbit transfer speed at max.