NVMe Thermal Throttling: Why Speed Drops as the SSD Heats Up
Sustained NVMe workloads can heat the controller enough to trigger automatic performance reduction.
What throttling is
Thermal throttling is a protective control that reduces activity when the device reaches a temperature target. It is designed to keep the controller and NAND within operating limits.
What it can look like
A benchmark may start near peak speed, then fall during later passes or long transfers. The pattern can overlap with cache exhaustion, so temperature and workload length should be considered together.
Cooling is system-specific
Motherboard heatsinks, laptop chassis design, airflow, nearby GPUs and ambient temperature all matter. A result from an open desktop bench is not a universal reference for a thin laptop.
How to test the hypothesis
Record idle temperature, run the same sustained workload, observe temperature and performance over time, then repeat after a cool-down. Consistent correlation is more useful than one screenshot.