TP-Link AD7200 network speed issue

I recently replaced my TP-Link AD7200 software/firmware with OpenWrt

All installation and configuration went out-of-the-box without any issues, but I see huge network speed slow down either in internal LAN or LAN to WAN for devices connected to router's RJ45 ports. I have yet made NO adjustments in openwrt configuration other than password and internal LAN subnet. All other settings are as they were done by the openwrt installation.
I played with "Enable packet steering across all CPUs" option but it have no visible effect on network speed.
I also played with turning off the 2.4Ghz and 5GHz Wifi, to see if it doesn't limit the overall transfer speed of the router's switch capabilities, without any effect.

All the ports (LAN and WAN) are 1Gbps and also OpenWrt switch configurator shows them as 1000baseT/Full duplex. But while measuring the speed using iperf tool between the LAN devices or using speedtest towards internet/wan, maximum speed which I can achieve is ~340Mbps.
With original TP-Link software/firmware the speed was always nearly 1Gbps in LAN and also in WAN. There is no change in cabling, so cables/connectors are the same as there were before.
See picture where the problem is clearly

I am wondering if this is a bug, or maybe some configuration option which I missed?
Thank you for help.


I faced same issue in 21.02.3 and rc4.
So far, I found following workaround/settings which increase bandwidth up to 900Mbit/s:

echo 1 > /proc/irq/37/smp_affinity
echo 2 > /proc/irq/38/smp_affinity
echo 3 > /sys/class/net/eth1/queues/rx-0/rps_cpus
echo 3 > /sys/class/net/eth1/queues/rx-1/rps_cpus
echo 256 >> /sys/class/net/eth0/queues/rx-0/rps_flow_cnt
echo 256 >> /sys/class/net/eth1/queues/rx-0/rps_flow_cnt
echo 3 > /sys/class/net/eth0/queues/tx-0/xps_cpus
echo 3 > /sys/class/net/eth1/queues/tx-0/xps_cpus
echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

LMK if it helps.