Orange Pi 3B Ethernet performance drops during long file transfers — how ca...

davidjohn68

Hi everyone,

I am testing an Orange Pi 3B as a small home file server running Ubuntu 22.04.5 LTS with Linux 5.10.160-rockchip-rk356x. The board has 2 GB RAM and is connected to a gigabit switch using Cat6 Ethernet.

The problem appears during sustained transfers rather than normal network use:

• First 1–2 minutes: around 92–95 MB/s
• After approximately 5 minutes: drops to 55–65 MB/s
• CPU usage during the slowdown: roughly 35–45%
• The same client PC can reach around 110 MB/s when transferring to another NAS
• iperf3 gives approximately 930 Mbps initially, but the result becomes less consistent after several minutes
• The Orange Pi temperature reaches about 68–72°C during the longer test
  

I have already tried another Ethernet cable, another switch port, and a different client machine. The behavior is still reproducible.

What I would like to determine is whether this is related to thermal throttling, Ethernet driver behavior, storage I/O, or the RK3566 performance governor.

For anyone running a similar Orange Pi 3B setup, which commands would you use to isolate the bottleneck? I can provide dmesg, ethtool, iostat, /sys/class/thermal/ readings, or a full iperf3 result if that helps.

I would especially appreciate a practical testing sequence rather than simply changing random kernel or network settings. Thanks!
Drift Hunters