Thermal ThrottlingDue 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).
In a pure read scenario, the drive doesn't throttle at all.
Without a fan, the drive throttles pretty quickly, after around a minute of full load, which is rather short. The temperature at which throttling starts seems rather low, too: only 63°C. We've seen other drives start throttling at much higher temperatures, and more gradually, which is something Crucial should consider for a future firmware revision.
Thermal Image & Hot Spot
We recorded a thermal image of the running SSD as it was completing the write test. The hottest part reached 79°C, which is significantly higher than what the drive's own SMART temperature monitoring reports, but not critically high in any way.