throughput is limited using KVM on XEON vs Ryzen

[godfather007]

Hi,

I'm using truenas scale as a hypervisor for OPN as VM
Giving them multiple cores, 2GB RAM, virtio NIC, latest OPN and tested on different platforms:

System1: and old kabini quad core @ 2.050 MHz
System2: an older Intel Xeon E5-2675 16 core @ 1.800 Mhz
System3: relative new AMD Ryzen 5 3400G 4 core @ 4000 Mhz

My Gbit internet readings are at:
System1: 350Mbit
System2: 750Mbit
System3: 975Mbit

System 1 and 2 get double the performance when providing multiple threads/core-counts but are limited to the readings above while the 3rd system can handle the Gbit speed with even 1 thread/core.

Even when i quadruple system 1 or 2, it does not matter. Readings stay the same and from the CPU indicator, on the mainpage of truenas, it looks like a single thread using 100% core time. Also getting multiple TCP streams does not affect the maximum speed, it stays limited.

Is this explainable by the CPU's frequency alone or should go to the tuning pages of BSD? I'm fine with my 750Mbit though, but just curious.


Thx for any substantiated insights