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.

Naked Drive without Heatsink

This test serves as baseline—the drive will thermally throttle after 45 seconds (read) and 24 seconds (write).

Heat Spreader

When adding the thin heat spreader that's in the box, throttling starts after 54 seconds (read) and 30 seconds (write), which confirms that the heat spreader has a positive effect on temperatures and can extend the time without throttling.

Drive with Thermalright Heatsink

Next, I installed a Thermalright TR-M2, which is a compact full-metal heatsink. Now throttling during reads was eliminated completely, writes throttled after almost six minutes.

Drive with Fan

Finally, to find out what's possible, I put a big 80 mm fan in front of the drive to achieve as low as possible temperatures. As expected, no thermal throttling.

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 76°C.