Download/Upload performance difference.

[enor]

I have a new default installation of opnsense where I have added 2 portfowarding rules.

Running with 10Gb dual nic and and an i5-12500 cpu(3Ghz, boost 4.1Ghz)
Installation is virtualized and using pci passthrugh for nic.

Been playing around with iperf3 and I notice that upload speed max out at ~9.37. Download jump around abit between 8-9.37. Guessing that when the CPU can't boost anymore speed goes down..

Why is there a difference? Ofc. there are a few firewall rules for incomming on WAN but not that many, have firewall rules between VLAN's but that does not drag down speed.
Is it translating back to local ip's which is more resource intensive then the other way?


In the end it does not really matter just curious.