I've observed a significant difference in SSH login speed between DietPi and Armbian on Raspberry Pi 4B (headless setup).
Environment
Raspberry Pi 4B (headless)
DietPi (recently installed)
Armbian (previously used)
Both systems use default settings
Observations
SSH login to DietPi is consistently faster than Armbian by a few seconds with default settings.
Initially suspected MOTD settings, tested files under /etc/update-motd.d/. Discovered that 10-armian-header adds approximately 1 second to login time. Disabled this component but SSH login to Armbian still remained slow.
Found related discussion on Raspberry Pi forums: SSH speed limit?
Used the following command for testing which revealed significant speed differences:
dd if=/dev/zero bs=1K count=1M | ssh localhost 'dd of=/dev/null'
and console log
root@DietPi:~# dd if=/dev/zero bs=1K count=1M |ssh localhost 'dd of=/dev/null'
root@localhost's password:
1048576+0 records in
1048576+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 12.9425 s, 83.0 MB/s
2097152+0 records in
2097152+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 9.35135 s, 115 MB/s
root@DietPi:~# uname -snrvm
Linux DietPi 6.12.47+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.47-1+rpt1 (2025-09-16) aarch64
root@rpi4b1:~# dd if=/dev/zero bs=1K count=1M |ssh localhost 'dd of=/dev/null'
root@localhost's password:
1048576+0 records in
1048576+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 29.5451 s, 36.3 MB/s
2097152+0 records in
2097152+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 20.0137 s, 53.7 MB/s
root@rpi4b1:~# uname -snrvm
Linux rpi4b1 6.12.19-current-bcm2711 #1 SMP PREEMPT Thu Mar 20 17:34:53 UTC 2025 aarch64
kernel config attachments
dietpi:
raspberrypi-config-6.12.47+rpt-rpi-v8.zip raspberrypi_proc_crypto.zip
armbian on rpi4b:
armbian-rpi-config-6.12.19-current-bcm2711.zip armbian_rpi_proc_crypto.zip
