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The real answer is: no one actually cares.

Very few people have the technical understanding required to make such a choice. And of those, fewer people still would actually pick SLC over QLC.

At the same time: a lot of people would, if facing a choice between a $50 1TB SSD and a $40 1TB SSD, pick the latter. So there's a big incentive to optimize on cost, and not a lot of incentive to optimize on anything else.

This "SLC only" mode exists in the firmware for the sake of a few very specific customers with very specific needs - the few B2B customers that are actually willing to pay that fee. And they don't get the $50 1TB SSD with a settings bit flipped - they pay a lot more, and with that, they get better QC, a better grade of NAND flash chips, extended thermal envelopes, performance guarantees, etc.

Most drives out there just use this "SLC" mode for caches, "hot spot" data and internal needs.

Agreed. I have some technical understanding of SLC’s advantages, but why would I choose it over QLC? My file system has checksums on data and metadata, my backup strategy is solid, my SSD is powered most days, and before it dies I’ll probably upgrade my computer for other reasons.

> Very few people have the technical understanding required to make such a choice. And of those, fewer people still would actually pick SLC over QLC.

There was a period of time when you could still by consumer SLC drives and pay a premium for them. I still have one.

Anyone assuming the manufacturers are missing out on a golden market opportunity of hidden SLC drive demand is missing the fact that they already offered these. They know how well (or rather, how poorly) they sell.

Even if consumers had full technical knowledge to make decisions, most would pick the TLC and QLC anyway. Some of these comments are talking about optimizing 20 year old drives for being used again two decades later, but ignoring the fact that a 20 year old drive is nearly useless and could be replaced by a superior option for $20 on eBay.

The only thing that would change, practically speaking, is that people looking for really old files on drives they haven’t powered up for 20 years wouldn’t be surprised that the were missing.

The rest of us will do just fine with our TLC drives and actual backups to backup services or backup mediums.

I’ll happily upgrade my SSD every 4-5 years and enjoy the extra capacity over SLC while still coming out money ahead and not losing data.

> But why won't the manufacturers let you choose? The real answer is clearly planned obsolescence.

No, it's not. The real answer is that customers (Even B2B) are extremely price sensitive.

Look, I know the prevailing view is that lower quality is some evil corporate plan to get you to purchase replacements on a more frequent basis, but the real truth is that consumers are price sensitive, short sighted, and often purchasing without full knowledge. There's a race to the bottom on price, which means quality suffers. You put your typical customer in front of two blenders at the appliance store, one is $20 and the other is $50, most customers will pick the $20 one, even when armed with the knowledge that the $50 version will last longer.

When it comes to QLC vs SLC, buyers don't care. They just want the maximum storage for the smallest price.

For your specific example, I would buy the $20 because I would assume the $50 is just as bad.

Having built computers casually for some time, I never recall being told by the marketing department or retailer that one kind of SSD was more reliable than another. The only thing that is ever advertised blatantly is speed and capacity. I saw the kind of SSD sometimes, but it was never explained what that meant to a consumer (the same way SMR hard drives were never advertised as having slow reads)

If I saw "this kind of SSD is reliable for 10 years and the other one is reliable for 2" then I may have made a decision based on that.

> I have an old SLC USB drive which is only 512MB, but it's nearly 20 years old and some of the very first files I wrote to it are still intact (I last checked several months ago

It's not about age of drive. It's how much time it spent without power.

Most of that time was unpowered and at room temperature (~20C).

Funny enough I just managed to find this exact post and comment on google 5 minutes ago when I started wondering whatever it's actually possible to use 1/4 of capacity in SLC mode.

Though what make me wonder is that some reviews of modern SSDs certainly mention that that pSCL is somewhat less than 25% of capacity, like 400GB pSLC cache for 2TB SSD:

https://www.tomshardware.com/pc-components/ssds/crucial-p310...

So you get more like 20% of SLC capacity at least on some SSDs

> do you want to have 4x more capacity at 1/100th the reliability?

Yes.

QLC SSDs are reliable enough for my day-to-day use, but even QLC storage is quite expensive and I wouldn't want to pay 4x (or realistically, way more than 4x) to get 2TB SLC M.2 drives instead of 2TB QLC M.2 drives.

NVMe protocol introduced namespaces. Is it not the feature perfect for users to decide themselves, how to create 2 virtual SSDs with TLC and pseudo-SLC-mode, choosing how much space to sacrifice for pSLC?

Most people want to use pSLC as cache or as the whole drive, not as a separate namespace.

> Alternatively: do you want to have 4x more capacity at 1/100th the reliability?

If the original drive has sufficient reliability, then yes I do want that.

And the majority of consumers do, too.

Chasing absolute extreme highest powered off durability is not a priority for 99% of people when the drives work properly for typical use cases. I have 5 year old SSDs where the wear data is still in the single digit percentages despite what I consider moderately heavy use.

> I have an old SLC USB drive which is only 512MB, but it's nearly 20 years old and some of the very first files I wrote to it are still intact (I last checked several months ago, and don't expect it's changed since then.) It has probably had a few hundred full-drive-writes over the years --- well worn-out by modern QLC/TLC standards, but barely-broken-in for SLC.

Barely broken in, but also only 512MB, very slow, and virtually useless by modern standards. The only positive is that the files are still intact on that old drive you dusted off.

This is why the market doesn’t care and why manufacturers are shipping TLC and QLC: They aren’t doing a planned obsolescence conspiracy. They know that 20 years from now or even 10 years from now that drive is going to be so outdated that you can get a faster, bigger new one for pocket change.

The only positive is that the files are still intact

WTF? That is the only reason to have non-volatile storage.

faster, bigger

I don't care one bit if it doesn't hold data long enough to not worry about while off. Otherwise it's just like RAM.

> If the industry was sane

Industry is sane in both the common and capitalist sense.

The year 2025 and people still buy 256Tb USB thumbdrives for $30, because nobody cares except for the price.