Wireguard performance

[Tiago Condeixa]

Hi,

I have been doing more experiments with heterogenous technologies and connections and there is a scenario where I believe that something strange is happening with wireguard.
When my board is using a 100 Mbps ethernet connection in a local network the iperf3 TCP is able to reach 95Mbps with the direct IP route, but when using wireguard the throughput reduces to 65/70 Mbps. 
It’s not a bad result at all, but I noticed that with wireguard the iperf3 CPU consumption goes from 10% to 70% when comparing with direct IP route. Do you have any idea why is this happening? ...the overall system CPU can slightly increase but I do not expect that happen with iperf3.
In other scenarios with other technologies and networks wireguard usually reduce 5% of the throughput but in this case it goes beyond 25%.

Thanks a lot,
Tiago