GoKawiilM.2-based SSDs have been around for about a decade now in PCs, and have all but replaced the much larger and notably slower 3.5-inch hard drives, and even 2.5-inch drives, both spinners and SSDs. Over that time, we’ve seen these tiny drives increase not only in capacity but also in speed as new flash, controllers, and PCIe generations are released. And with that increase in performance comes increased heat that you need to manage. This is especially true when using the latest-generation PCIe 5.0-based drives, which tend to run hotter than previous-generation drives and are more prone to thermal throttling and performance loss.
Many of these drives already come with heatsinks to help manage thermal output. And so long as it isn’t a simple thin plate, many do the job well enough to either delay or prevent thermal throttling.
However, not all include heatsinks, and if your workflows lean on storage, longer transfers can be significantly slower due to the drive overheating and thermal throttling. The amount of throttling, if any at all (some actually won’t), varies by circumstance. Whether by drive and controller, workload, and even case airflow, these factors affect whether you’ll see thermal throttling and how severe it is. If time is money, this is obviously a bad thing. The longer it takes to read or write the files you need, the longer it takes to finish your work and get to something more pleasurable, or move on to the next task.
Latest Videos From Tom's Hardware Watch full video here:
(Image credit: Tom's Hardware)
You may be thinking: My motherboard has heatsinks for M.2 drives, and of course, if you aren’t using a bargain-basement or business board, you would be right. Those also come in all shapes and sizes (plate-style to massive), with varying cooling capabilities. In general, the more mass a cooler has and the greater its surface area, the better it can cool. There are other variables, including thermal pad efficiency, chassis airflow, and, of course, physical contact, but at a high level, this is the way.
But we wondered if these motherboard heatsinks actually make good contact to whisk away the heat? After seeing seemingly random complaints online in forums and on Reddit over the years, we tested the primary M.2 heatsink from the top PCIe 5.0 M.2 socket on 20 different motherboards to see how many actually make good contact with the included heatsink. And I was honestly a bit surprised at what we found.
So what does thermal throttling look like on M.2 drives? It’s a sudden, typically severe, drop in data transfer speeds, appearing as a sharp cliff where blazing-fast speeds plummet to a fraction of the drive’s rated performance, or a saw-tooth pattern where it drops, cools below the critical temperature thresholds (typically by reducing the duty cycle and capping the IO stream and data bandwidth), then jumps back up. Some drives even drop back to PCIe 4.0 to limit bandwidth and reduce thermal throttling.
As you can see from the charts below (which contain throttled and non-throttled results from the same drive), the heatsink-less Transcend 260S 2TB PCIe 5.0 SSD we used for this testing throttled just after the 50-second mark, dropping from just under 4,000 MB/s to around 1,700 MB/s. It then briefly recovered after dropping below its critical temperature threshold (typically between 70 and 85 degrees Celsius) around 90 seconds into the transfer. Several seconds later, it dropped again, and minutes later, it dropped again, this time slowing performance even further to around 600 MB/s, over six times slower than its steady-state performance and much closer to SATA-based SSDs than PCIe 5.0.
Stay On the Cutting Edge: Get the Tom's Hardware Newsletter Get Tom's Hardware's best news and in-depth reviews, straight to your inbox. Contact me with news and offers from other Future brands Receive email from us on behalf of our trusted partners or sponsors
... continue reading