I recently replaced my TP-Link AD7200 software/firmware with OpenWrt
http://downloads.openwrt.org/releases/21.02.0/targets/ipq806x/generic/openwrt-21.02.0-ipq806x-generic-tplink_ad7200-squashfs-factory.bin
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 https://imgur.com/a/xG4OtOX
I am wondering if this is a bug, or maybe some configuration option which I missed?
Thank you for help.