Thermal Throttling

Due to the compact form factor, M.2 drives lack the ability to actively cool themselves, usually having to rely on passive airflow instead. All vendors include some form of thermal throttling on their drives as a safeguard, 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, installed in the M.2 slot between the CPU and VGA card, while it's getting hammered by non-stop incoming writes. A first test run, to create a baseline, shows temperature and performance with a 120 mm fan directly blowing on the tested drive. In a second run we report thermal performance of the completely uncooled 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 degrees Celsius (measured using SMART).

Results from this test setup are not comparable to our older SSD benches because we're using a different case and an AIO watercooling unit, so there's very little airflow inside the case.

Reads

Writes

With an additional fan blowing on the heatsink, there's no thermal throttling. Without a fan, there's a tiny bit of thermal throttling during writes, but it takes a long time to reach that—over four minutes at full speed. The throttling is very well-behaved and gradual. Reads do not result in throttling.

Without Heatsink

Without any heatsink and with very little airflow, the drive will throttle rather quickly, but it will not crash, and the throttling is not too aggressive.

Thermal Image & Hot Spot

We recorded a thermal image of the running SSD as it was completing the write test. The surface temperature of the drive reached 87°C, which is close enough to the software sensor readings.