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.

Some charts say "Phison E31 ES", they are actually for the Team Group G50, I just forgot to set the correct title

Heat Spreader + Fan

This test serves as baseline—no thermal throttling.

Heat Spreader

If we remove the fan and run with the heat spreader there's some thermal throttling in both reads and writes, but it takes a while before that happens.

Naked Drive without heatsink

The drive without heat spreader will thermally throttle very quickly, which confirms that the heat spreader helps lower the temperatures.

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 100°C, which is still fine as thermal throttling will keep the drive at safe temperature levels.