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 without Heat Sink

Reads with Heat Sink

Writes without Heat Sink

Writes with Heat Sink

Without the heatsink, there's some gradual thermal throttling as the drive heats up. In the "worst" throttle state, the performance still reaches a sustained 2 GB/s, which is outstanding.

Once the heatsink is installed, the throttling during writes without fan happens much later, and "avoids" the 2 GB/s speed zone, staying at 3 GB/s instead.

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 heatsink reached 101°C, a reasonable maximum. The on-drive thermal sensors were completely wrong, reporting only 60°C.


With the heat spreader installed, temperatures are much better, the surface of the cooler reaches 75°C.