1
Diagnostic step 1
Reproduce with incremental telemetry: run a controlled fio sequential-write test while capturing smartctl -a (every 10s), iostat (1s), and dmesg -w > nvme.log; keep system idle except for test.
FULL AI ANALYSIS
NVMe SSD shows high latency and occasional I/O errors during sustained writes on Ubuntu 22.04
Generated Oct 3, 2026, 12:35:03 AM
Analysis summary
Symptoms strongly point to a thermally-triggered performance throttle or internal NVMe controller fault: rapid temperature rise to >90°C, nvme timeouts in kernel logs, and sustained throughput collapse all fit a thermal-protection or firmware-level recovery. Less likely but possible are poor M.2 slot cooling, BIOS M.2 power limit, or PCIe lane/link negotiation issues. Collecting controlled telemetry (temperature, SMART error counters, kernel nvme traces) while isolating variables (different slot, passive cooling, reduced PCIe link speed) will narrow the root cause.
Possible causes
NVMe internal thermal throttling / emergency shutdown when controller reaches critical temperature
90%SSD firmware bug causing controller resets under sustained sequential writes
60%Motherboard M.2 slot power delivery or BIOS power-limit/cooling configuration causing overheating
30%PCIe lane/link negotiation problems under sustained throughput (e.g., thermal stress causing link drops leading to kernel timeouts)
25%Suggested fixes
2
Diagnostic step 2
Attach an external IR thermometer or thermocouple to the M.2 heatsink and record surface temperature; compare to SMART temperature. Use passive heatsink or increase airflow (desktop case fan) and rerun test to check if behavior improves (reversible).
3
Diagnostic step 3
Boot a recent live USB (Ubuntu 24.04 or vendor's diagnostic ISO) and repeat a short stress test to rule out kernel regression; collect nvme-cli logs (nvme list, nvme smart-log /dev/nvme0).
4
Diagnostic step 4
Temporarily limit fio throughput to safe levels (e.g., using --rate or lower block size) and see whether errors disappear; this avoids destructive testing while validating thermal threshold.
5
Diagnostic step 5
If moving the SSD to a different physical M.2 socket changes behavior, capture BIOS firmware version and disable any M.2 slot-specific settings (PCIe link speed, power-saving) and update motherboard BIOS; document all steps before changing settings permanently.