Thermal Throttling

Due to the compact form factor, M.2 drives lack the ability to cool themselves and usually have to rely on passive airflow instead. As a safeguard, all vendors include some form of thermal throttling on their drives, which limits the throughput once a certain temperature is exceeded.

On this page, we will investigate whether the tested drive has such a mechanism, how high temperatures get, and what effect this has on performance. We will test the drive installed in a typical case, in the M.2 slot between the CPU and VGA card. A second data point is provided which shows the result when a 120 mm fan is blowing directly on the tested drive. Each of the charts has time moving from left to right, with the blue line displaying transfer speed in MB/s and the red line showing the temperature in °C (measured using SMART).


In a pure read scenario, the drive doesn't get warm enough to start throttling.


With heavy writes, the drive will start throttling once it reaches 66°C, and speeds drop to ~220 MB/s. Once that speed limit had its effect and temperatures are reduced, performance will be restored until temperature gets too high again. With the SSD cooled by the fan, we see no such behaviour.

Thermal Image & Hot Spot

During the write test, we recorded a thermal image of the running SSD. The hottest part, which seems to be the controller, reaches 90°C. This means that the temperature reported by the drive itself (65°C max) seems very optimistic, or that the sensor is located far away from the hottest sections of the drive.