Archer C7 v4 - iPerf3 reports only ~300Mbit/s via LAN

Hi all,

My Setup (all cabled): ISP Fritzbox -> OPNsense box -> Archer C7 v4 -> MacBook
Version: OpenWrt 19.07.2 r10947-65030d81f3
Kernel: 4.14.171

I just got my ISP connection upgraded to 1000Mbit coming from 300Mbit.
That´s why I never had the feeling that I don´t get the maximum speed out of my box.
Now I still don´t get faster results compared with my old bandwidth, even though I get ~940Mbit when I´m connected directly to my ISP´s Fritzbox. I installed iperf3 on the Archer which acts as my iperf server atm.

So now I´m currently only testing the connection between my MacBook and the Archer. Just configured 2.4 and 5GHz Wifi and an additional Guest Wifi running through a seperated VLAN to my OPNsense.
Everything else is default out of the box!

Any hints how I can speed it up? I remember that I went back to the OEM firmware due to bandwidth issues as well but it is already a few years ago... I don´t want to revert but do I have to?

Don't run iperf on this low powered archer device as iperf is very ressource hungry on hight line speeds.

Even if you run iPerf on a separate box, don't expect the C7 to route at gigabit. Maybe it will hit 500 or so. Maybe with all the latest flow-offloading enabled it might do better.

with software offload it can reach over 700mbps ethernet