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 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 in a typical case, in the M.2 slot between the CPU and VGA card. A second data point 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).

Reads

In a pure read scenario, the drive doesn't throttle at all.

Writes

Without a fan, the drive will start throttling once its internal temperature monitoring reports around 80°C. The throttling is fairly well-behaved, though, as it only drops from 2 GB/s to 1.5 GB/s and not all the way down to keep the drive's temperature in check. To put things into perspective, at 2 GB/s, for 150 seconds, the drive will only start thermal throttling after 300 GB of data have been written.

Thermal Image & Hot Spot

We recorded a thermal image of the running SSD as it was completing the write test. The hottest part reached 102°C, which is significantly higher than what the drive's own SMART temperature monitoring reports.