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.

Drive with Stock Heatsink

First, I've tested the drive with the stock heatsink, with no additional airflow around the M.2 socket. During reads the drive throttles after 3 minutes, during writes after just a few seconds. While this doesn't look good for the thermal stress test that we're running, for all normal consumer scenarios this should be good enough—it's highly unlikely that you'll be writing so much data in such a short time.

Drive with Thermalright Heatsink

Next, I installed a Thermalright TR-M2, which is a compact full-metal heatsink. Throttling definitely happened earlier than with the Klevv heatsink, which confirms that the Klevv cooling solution is working well and can compete with similar-sized alternatives.

Drive with big Thermalright Heatsink

Using a big Thermalright HR-10, which is still passively cooled, but using two heatpipes, we can see that thermal throttle happens much later and is less aggressive, but the drawback is that you have to fit the larger design and throttling can't be eliminated completely.

Drive with Fan

Finally, to find out what's possible, I put a big 80 mm fan in front of the drive with the stock heatsink, 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 81°C.