Ho trovato il video (o meglio lo spezzone) di Gamers Nexus. Di base il discorso secondo me è condivisibile ma incompleto e quindi un po' fuorviante, perché se è vero che i le memorie NAND degradano meno velocemente se le scritture avvengono ad alta temperatura (è facile trovare non solo dati JEDEC ma anche paper in merito), la ritenzione dei dati
già memorizzati diminuisce ad alta temperatura.
Inoltre, pensandoci un po' sopra, credo proprio che questo accada anche ad SSD alimentato o comunque connesso a PC acceso, dato che gran parte della circuteria (incluse le memorie) di fatto è spenta in idle a causa della gestione energetica. Altrimenti, non ci sarebbero stati problemi simili con i vecchi Samsung 840, dove il decadimento sui dati vecchi accadeva anche a PC acceso.
Ask GN 90: M.2 Heatsinks Kill SSDs? Is AMD Losing Long-Run?
https://www.youtube.com/watch?v=KzSIfxHppPY&t=375s
Quote:
[07:27] [...] The problem is, you know, you really don't want to [heat-]sink the NAND if you're going to be writing a whole a lot. And that's because there is degradation, because NAND (the flash) actually prefers to be warmer while it's doing writes. And you may have read of cold storage. If you are storing it, then you want it to be cold, but if it's active then you want it to be warm. The controller to a point should be cooler so that it doesn't throttle, but the point of thermal throttle is rare to hit, which is something [Allyn Malventano] talked to us. Let me read you his answer here. Allyn said:
Quote:
JEDEC rates client SSDs with an operating temperature of 40C. If you force the flash down closer to room temperature (25C), then with the same amount of writing (done at that lower temperature) the end of life data retention time will be cut in half. An M.2 SSD without a heatsink will naturally rise above ambient. Same goes for SSDs with heat spreaders / heat spreading labels (they just spread the heat more evenly, which is actually better for endurance since the flash will also run slightly warmer even while idle)
Now for the heatsink / water block problem. The goal of these items is to prevenet thermal throttling during heavy use, but that is a controller issue, not a flash issue (flash loves to be hot while operating - specifically during writes as that is what causes the wear). Where the heatsink/block makers get this wrong is by having the thermal pad contact the flash. We want it to only contact the controller. Yes, the overall temp will still run lower (less controller heat conducting to the flash while idle), but at least during heavy writes, the flash will be able to rise closer to its preferred temperature without the heatsink actively pulling it back down to ambient.
This is far less of a concern for a showpiece system that is rarely writing, but I would still recommend trimming the thermal pad so that it only contacts the controller
--Allyn Malventano of PCPer
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[09:31] I had a bit more of a discussion with him, he gave me a chart that hopefully we can put on the screen at some point during this, with some temperatures at power off and Active temperature that you can look at.
[img]
And also we talked about overall personal takes on these heat sink devices for M.2 SSDs and Allyn noted that generally throttling is going to be the reason to actively cool the SSD, on the controller that is, and thermal throttling (...) pretty hard to do except in benchmarks that might not be realistic. So, if you know you're throttling then it's useful, but if not it might not be worth buying. And things like the labels that are built-in, the heat-spreading labels, the built-in heatsinks on some devices (...), those can do an OK job in some instances. And the main thing is just... maybe consider trimming the thermal pad like Allyn was saying.
[10:28] We have one more thing to talk about that I wanted to bring up. A great way to deal wth a controller overheating in rare cases [...] is put some thermal pads between the controller and the motherboard if it's dual sides, or even just on the back side of the PCB of the SSD and the motherboard. Because the motherboard is a natural heat sink: it's made of fiberglass and copper basically. So you put a thermal pad between the controller and the [motherboard], whether it's the backside or the front side, that will sink some heat and that's going to be targeted, it won't cool the NAND so you don't have to worry about that at all. Also, average case temperature tends to be about upper 30-35 C in an environment that's 25C. So just some more information for you.
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