The problem of heat dissipation in high-performance, small form-factor SSDs is well-known, for example, the paper Transient Thermal Analysis for M.2 SSD Thermal Throttling published in 2018 17th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems states:
Solid State Drive (SSD) technology continues to advance toward smaller footprints with higher bandwidth and adoption of new I/O interfaces in the PC market segment. Power performance requirements are tightening in the design process to address specific requirement along with the development of SSD technology. To meet this aggressive requirement of performance, one major issue is thermal throttling. As the NAND and ASIC junction temperatures approach their safe operating limits, performance throttling is triggered and thus power consumption would drop accordingly.
Naturally, if space allows, adding a huge heatsink is a possible solution to this problem, there are many products available on the PC gaming market. I also see many M.2 to PCI-E passive adapters on the market have built-in heatsinks by adding a huge copper pour with connection to the ground plane under the M.2 connector.
But one can find many unsourced posts on random computer hardware forums, which claims that the NAND chips should never be cooled. It is claimed that they are actually designed to heat itself up to an optimum operating temperature, and adding a heatsink to the NAND chips adversely affect its reliability. Here's some examples.
One claim reads,
Don't cool the NAND dies themselves!
They heat themselves up to operating temperature by design, cooling them means they just continually dump out power trying to hit temperature, and will be operating with a lower endurance (simplified: higher operating temperature = lower energy input to set/erase cells = less degradation of each cell per write/erase cycle).
Another claim reads,
Cooling the NAND is bad. You want the NAND to run warm and stay warm. As its temperature fluctuates, and as it cools down, if you suddenly transfer a large file (read or write, I can't remember) while the NAND hasn't had time to warm back up first, it can significantly reduce the life of the NAND.
It doesn't sound right to me. It suggest that the NAND chips depend on the self-heating effect to reach an optimum operating temperature, which is something I've never heard before. The only chips that I know that use self-heating are National's LM199/299/399 "Super Zener" voltage references, and Linear Technology's LT1088 Thermal RMS-DC Converter. But I don't believe NAND chips have anything to do with self-heating.
I tried to fact-check and/or debunk these statement, start by looking for a NAND chip datasheet found in some recent SSDs. I went to Digikey and Mouser, set the filter to the highest storage density and sorted them by prices. Unfortunately, it seems that datasheets are not available (all under NDA? I'm looking at the wrong place?).
Are these strange statements have any factual basis?