IPSEC performance problem

Be sure they do it.
They use a few tricks to mislead:

  1. they use UDP instead of TCP, despite the fact that ALL file transfer protocols (FTP, HTTP, SCP, SFTP, SMB) use TCP.
    VPN tunnels on Mikrotik hardware routers shows good speed with UDP, but has very poor speed with TCP - you can find many topics on the forum about these issues, for example L2TP/IPSec VPN performance on 1G links
  2. they use two streams (instead of single stream) for single tunnel, which doubles the total Mbps (one stream is limited by the speed of one core).

For real life results they should publish the results of TCP single stream! (and preferably using an iperf, not a Traffic Generator)