If I place my laptop next to the router I can get up 800mbps over iperf3, but never anywhere over 350 on Ookla Speedtest/fast.com, etc. My ethernet devices can connect and pull down the full 900mbps I get from my ISP.
For reference, here's some speed tests I just completed on my phone (Wi-Fi), and my desktop (ethernet)
My router is a Belkin RT3200/Linksys E8450 running OpenWrt 22.03.0 r19685-512e76967f.
What's the actual question?
Does iperf report retransmissions?
How did you perform the iperf3 internal tests?
If you ran iperf3 direct on the router, then you are only measuring the capable speed from the LAN interface to the iphone/desktop PC. ie. you are not measuring throughput from WAN to LAN interfaces.
I ran iPerf3 from my phone to a Linux server device on my network connected to ethernet.
No, it doesn't show anything. Just the bandwidth & time.
Did you find solution? I have exactly the same issue on Xiaomi AX3200. It have the same SOC, so I think the issue is the same.
In addition, hardware flow offloading does not work via Wi-Fi, it works on LAN interfaces only.
In more detail, the issue is as follows.
The wi-fi 6 client is connected at 1200Mbps.
Nas is connected by 1Gbps cable to LAN.
Speedtest.net run from Nas gives me speed of about UL/DL 300/300 Mbps.
The speedtest.net test with the same parameters, run from a laptop via LAN 1Gbps, gives a speed of UL / DL 300/300 Mbps.
The speedtest.net test with the same parameters, run from a laptop via Wi-Fi6, gives a maximum speed of UL / DL 100/200 Mbps (and more often around 70Mbps)
Also, iperf between a laptop via Wi-Fi and a NAS via LAN gives a normal result of the order of 600-800 Mbps