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.

Bare Drive without Heatsink

Samsung ships this variant of their drive without a heatsink, so I ran our first test without the heatsink, without any additional airflow. As you can see, the drive throttles fairly quickly. On the other hand, if you have only light workloads that last for less than a minute, then throttling won't be an issue. While writes are pretty slow with 1 GB/s during throttling, reads are quite alright with 2-5 GB/s.

Drive with Thermalright Heatsink

Next, I installed a Thermalright TR-M2, which is a compact full-metal heatsink. Still quite some throttling, but much better.

Drive with big Thermalright Heatsink

With the much bigger Thermalright HR-10, there is no more throttling.

Drive with Fan

Finally, as control, I put a big 80 mm fan in front of the drive without heatsink, no throttling here, either.

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 106°C, which is much higher than what the thermal sensor reports. Do note that two sensors are exposed, but both show exactly the same value.