Intel ushered in, for the most part, the era of PCIe 5.0 with its 12th Gen Alder Lake platform and soon AMD will also have it with its upcoming Zen 4 CPUs and Socket AM5 LGA1718 motherboards. While the progress made by PCIe hasn't had much of an impact on GPUs, storage devices have had a different story to tell as the increased throughput has been a boon for NVMe drives.
And with PCIe 5.0, a 4-lane (x4) motherboard the bandwidth is expected to reach 16GB/s meaning premium high-quality NVMe SSDs could be reaching close to those speeds. With great speed comes great heat and NAND flash is known to be very heat-sensitive.
To keep it all cool, Sebastien Jean, Chief Technical Officer at Phison, believes it could become the norm for the next-gen PCIe 5.0 SSDs to feature active cooling with fans alongside heatsinks, probably similar to the one shown in the image above.
There are lots of things that we’re doing to keep the SSD power within a reasonable envelope, but for sure, the SSDs are going to be hotter, in the same way that CPU and GPU got hotter in the 1990s. As we move to Gen5 and Gen6, we may need to consider active cooling.
As mentioned above, heat is bad for NAND. In fact, not just heat, but cold can be bad too as it could lead to large temperature swings making the NAND chips prone to more error corrections. Jean has explained that the ideal operating temperature for SSDs is 25-50 °C or 77 to 122 F:
The controller and all the other components … are good up to 125 degrees Celsius (257 degrees F), but the NAND isn’t, and the SSD will go into critical shutdown if it detects that the temperature of the NAND is above 80 degrees Celsius (176 degrees F) or so.
[..] If most of your data was written really hot and you read it really cold, you have a huge cross-temp swing. The SSD is designed to handle that, but it translates into more error corrections. So lower maximum throughput. The sweet spot for an SSD is between 25 and 50 Celsius (77 to 122 degrees F).
As for what the future holds in terms of cooling SSDs, the Phison blog post also briefly mentions that a successor to M.2 connectors is in development as the current implementation will begin to bottleneck soon. As such, better heat transfer solutions are also expected to follow.