Hi,
I’ve been chasing an intermittent packet loss issue on my Pi 5 for a while now and could use some outside perspective on what I’ve found.
Setup:
- Raspberry Pi 5
- Connected through a Horaco 8-port 2.5GbE + 1x SFP+ unmanaged switch
- Also on the Pi: a bus-powered USB SATA SSD (Samsung 870 EVO) and a SkyConnect/ZBT-1 dongle
- Official 27W USB-C PSU
Packet loss pinging the router (single hop, 192.168.88.1), measured via HA’s built-in ping integration and cross-checked with the Network Monitoring Add-on doing continuous 1-second pings. Loss bounces between 0% and 30%, no consistent pattern tied to time of day.
What I’ve ruled out:
- Undervoltage — nothing in
dmesg | grep -i volt, nothing in HAOS Settings → System → Repairs - NIC-level errors —
/sys/class/net/end0/statistics/*(rx_errors, rx_dropped, rx_crc_errors, rx_fifo_errors, tx_errors) all read 0, even during periods of high measured loss - Bad cable — swapped the patch cable between Pi and switch, no change
- Switch port — tried a different port, no change
- Other devices on the same switch — no packet loss observed on them
- CPU load / thermal throttling — checked history during loss windows, CPU stayed under 10%, temps normal (55-63°C)
The Network Monitoring Add-on runs a continuous 1-second ping to the router in the background. Each time I stop/remove it, packet loss (as reported by HA’s ping integration) rises within seconds and stays elevated (10-30%+). Each time I start it again with the same continuous ping, loss drops back to near 0% and stays there. This has now happened twice, in both directions, so it doesn’t look like a one-off coincidence.
NIC error counters stay at zero throughout, in both states — so whatever this is, it’s not showing up as corrupted frames. It looks tied to whether there’s constant traffic keeping the link active, rather than a hardware fault in the usual sense.
Has anyone seen packet loss on a Pi 5’s onboard Ethernet that correlates this cleanly with idle vs. constantly-active traffic? Trying to figure out if this points to something specific (EEE/power state related, or something else) before I draw conclusions.
Any ideas? I know it´s an AI slop but whatever…