Who is selling pure SLC NVMe SSD?

[Chiyawa]

Well, the recent LTT did showcase an NVMe drive from Entomus (I believe) that has SLC and QLC mixed, so that makes me wonder: Is there a pure SLC NVMe SSD out there? I think Intel Optane uses SLC, but it is only serve as cache drive instead of usable drive that can install Operating System into it.

 

Regards,

Chiyawa

[Applefreak]

12 minutes ago, Chiyawa said:

Well, the recent LTT did showcase an NVMe drive from Entomus (I believe) that has SLC and QLC mixed, so that makes me wonder: Is there a pure SLC NVMe SSD out there? I think Intel Optane uses SLC, but it is only serve as cache drive instead of usable drive that can install Operating System into it.

 

Regards,

Chiyawa

Some hard to find enterprise SSDs as well as Intel Optane. However those cost 10x or more the price of MLC SSDs. Look at the Intel Optane SSD 905P for example. It can be used as a OS or system drive if you like.

[NunoLava1998]

Just now, Applefreak said:

Some hard to find enterprise SSDs as well as Intel Optane. However those cost 10x or more the price of MLC SSDs.

Not to mention Optane SSDs were recently discontinued, so if you want one you'll have to buy one pretty much now.

They're fast though!! Can't lie abt that

[mariushm]

Optane is a different kind of Flash memory than the one which has memory cells that can keep 1 to 4 bits per cell (SLC, MLC, TLC, QLC) 

 

The drive in the LTT video uses QLC memory, but part of the QLC memory chips is used in "pseudo-slc" mode, where each qlc cell stores 1 bit instead of 4 ... because it takes less time for the charge to be set in the cell (0 % or 100% is easier to set than one of 16 levels)  you get faster read/writes and higher endurance.

 

Actual SLC memory is pretty much not used anymore, except in some special circumstances (ex 8-16 GB industrial sata drives etc) .. it's too expensive to make and controllers have advanced so much that you get good enough performance with MLC which is much cheaper. 

You can find MLC based nvme drives easier... some of them will also have some amount of "pseudo-slc" memory. 

 

Sandisk's (and WD's because WD bought Sandisk) use pseudo-slc with TLC memory as well... as do other manufacturers.

[Archer42]

45 minutes ago, mariushm said:

Optane is a different kind of Flash memory than the one which has memory cells that can keep 1 to 4 bits per cell (SLC, MLC, TLC, QLC)

No, it is not. It is a different type of non-volatile memory altogether, nothing to do with flash.

 

58 minutes ago, Chiyawa said:

Well, the recent LTT did showcase an NVMe drive from Entomus (I believe) that has SLC and QLC mixed, so that makes me wonder: Is there a pure SLC NVMe SSD out there?

SLC is basically not even produced nowadays. There are things like samsung z-ssd which run modern flash in slc mode, but no real slc apart from, may be, some industrial applications where required storage is very small (and even there it is becoming basically non-existent at this point).

Why? Because it makes no sense commercially. Almost nobody wants this, and producing small amounts of such memory will be so expensive even those who wanted would not buy it.  The same reason MLC is disappearing too...

 

58 minutes ago, Chiyawa said:

I think Intel Optane uses SLC, but it is only serve as cache drive instead of usable drive that can install Operating System into it.

All optane stuff is just an ssd + caching software. You can install OS even on those modules which were sold specifically for caching, like M10, as long as it fits.

There is also stuff like 900/905p (discontinued) and new pci-e 4.0 ones - P5800X. They are a bit expensive but you definitely can use it just like any other ssd.

But then... they are not really "SLC". Different memory type altogether. Nothing to do with flash or related terminology. Store only one bit per cell though, so if you really want you might call it "SLC".

[porina]

39 minutes ago, Archer42 said:

All optane stuff is just an ssd + caching software.

Optane is just Intel's marketing name for Xpoint technology. Nothing to do with software, which only applies specifically to Optane Memory. Most other types of Optane can be used like regular SSDs, exception being Optane DIMMs. They are a level beyond any flash based, even SLC. The only problem for consumers is cost. You pay for that performance, and generally speaking it is not needed in consumer use cases. Optane is so fast CPUs limit their performance. You can see the random IOPS go up from overclocking CPU. It's insane fast at that if only it wasn't held back by the PCIe bus latency.

[Archer42]

11 minutes ago, porina said:

Optane is just Intel's marketing name for Xpoint technology.

More like a product name, yes.

What i meant is 90% of their marketing was about caching, which confused OP too, and caching is pure software.

By the way on "supported platforms" other optane branded products like 900p/905p/800p which are not called "memory" can be used by that software for caching too.

[Chiyawa]

1 hour ago, Applefreak said:

Some hard to find enterprise SSDs as well as Intel Optane. However those cost 10x or more the price of MLC SSDs. Look at the Intel Optane SSD 905P for example. It can be used as a OS or system drive if you like.

I see. Thanks for the info.

 

1 hour ago, NunoLava1998 said:

Not to mention Optane SSDs were recently discontinued, so if you want one you'll have to buy one pretty much now.

They're fast though!! Can't lie abt that

Oh dear. Well, I better start hunting for 1 then

 

1 hour ago, mariushm said:

because it takes less time for the charge to be set in the cell (0 % or 100% is easier to set than one of 16 levels)  you get faster read/writes and higher endurance.

Actually, that's the reason I'm looking for one. I mean, I have some sensitive information in my SSD. Although I do a regular backups to a HDD, I'm still not quite confident with my SSD not failing unexpectedly.

 

Also, the speed as well.

 

1 hour ago, Archer42 said:

Why? Because it makes no sense commercially.

Yeah. And it's sad to see they are disappearing.

 

22 minutes ago, porina said:

Most other types of Optane can be used like regular SSDs, exception being Optane DIMMs.

Hmm... Is that so? Well, I'm not really dive deep into Optane technology, so I'm not well aware.

 

7 minutes ago, Archer42 said:

By the way on "supported platforms" other optane branded products like 900p/905p/800p which are not called "memory" can be used by that software for caching too.

I see. Good to know.

[Archer42]

15 minutes ago, Chiyawa said:

Oh dear. Well, I better start hunting for 1 then

They are still selling new DC ones, which are even more crazy, both in terms of performance and price.

 

Also be aware that they all pretty power hungry and hot, including 900p/905p. I have 960GB 905p U.2 one and without fan blowing right at it temperatures can be as high as ~50C idle despite it's form factor (basically a 2.5 inch heatsink). And this makes sense when you look at specs - idle power consumption is pretty high.

I would not recommend buying the only m.2 version of 905 which exists for this reason.

[Chiyawa]

Oh, by the way:

 

We can jam pack multi terabytes of data into SSD using TLC or QLC, can we employ the same technology for RAM?

[Chiyawa]

2 minutes ago, Archer42 said:

They are still selling new DC ones, which are even more crazy, both in terms of performance and price.

 

Also be aware that they all pretty power hungry and hot, including 900p/905p. I have 960GB 905p U.2 one and without fan blowing right at it temperatures can be as high as ~50C idle despite it's form factor (basically a 2.5 inch heatsink). And this makes sense when you look at specs - idle power consumption is pretty high.

I would not recommend buying the only m.2 version of 905 which exists for this reason.

Yeah, I think I heard about it getting pretty warm. After all, it was meant for data centre and servers as it needs to be always active.

[Doobeedoo]

Yeah pure SLC SSD are no more, even MLC as of late. I'd really like to see Samsung release their Z-SSD for consumers.

[andrewmm]

Im a little late to this thread,

 

Im investigating SLC / T:C / MLC storage, 

    

In particular at temperature with no power on the M.2 

 

I'm getting shocking results, 

   After a month at 55 degrees, with no power, all the MLC and the TLC flash chips have errors, 

 

The SLC are just fine. 

 

So there is a reason to go for SLC 

 

[Chiyawa]

14 hours ago, andrewmm said:

Im a little late to this thread,

 

Im investigating SLC / T:C / MLC storage, 

    

In particular at temperature with no power on the M.2 

 

I'm getting shocking results, 

   After a month at 55 degrees, with no power, all the MLC and the TLC flash chips have errors, 

 

The SLC are just fine. 

 

So there is a reason to go for SLC 

 

Of course, but many favours the high density over reliability and speed.

[NewMaxx]

You can certainly get pSLC drives made from industrial TLC which are good for ~40K P/E and have good retention characteristics.

[Chiyawa]

30 minutes ago, NewMaxx said:

You can certainly get pSLC drives made from industrial TLC which are good for ~40K P/E and have good retention characteristics.

Indeed. Now I don't think any drive manufacturer produce SLC any more.

[NewMaxx]

21 hours ago, Chiyawa said:

Indeed. Now I don't think any drive manufacturer produce SLC any more.

No, they absolutely do, but it's made as SCM (storage class memory) so is optimized for ultra low latency to compete with things like memristors and PCM (phase change memory). By that I mean, you can't compare TLC/QLC in pSLC mode to it, SLC is now created for very specific applications which means it's an order-of-magnitude faster. So it's not really comparable to what we used to have with e.g. SLC vs MLC in earlier consumer drives.

[Avid0g]

Transcend released an announcement for pure "SLC mode" m.2 NVMe, but I don't see any sales with the model number format: TSxxGMTS052Tx

 

https://www.guru3d.com/news-story/trancend-releases-high-durability-m-2-ssd-adopting-slc-mode-with-100-000-rewrites.html

[kokosnh]

those are TLC in pSLC mode, some chia SSD did just that from TLC or QLC NAND. 

 

but going back to optane, going just from my memory couple years old, it is just a NAND with heating element, so it can do 250C on the write ( similar in teory to HAMR in HDD, but going for totally different physical phenomena ). and it to can be SLC / MLC / TLC ( or i’m mixing it up with diffrent type of memory I read once. I remember there was also this one NAND, that could self heal with heating element). 

[Avid0g]

The Micron M600 flash drives with 256 or 512 GB capacity will effectively operate 100% in SLC mode while under 48% full. Above that capacity it begins storing and consolidating data as MLC. It might be hard to find anything but used SSD. 

Only the M.2 NVMe versions can take full advantage of that speed. The eSATA version is somewhat hobbled by the interface. 

 

Also look into the Samsung 970 EVO Plus SSD. It also has a variable size cache, so it probably implements that with cells configured as SLC. I suspect you can allocate part of the internal cache as DRAM swap space. 

[Cacahuete Frito]

<https://www.digikey.com/en/products/filter/solid-state-drives-ssds-hard-disk-drives-hdds/503?s=N4IgjCBcpgLAnFUBjKAzAhgGwM4FMAaEAeygG0QEAOAJgHY6Qi6A2AVhbDacvlqoDMIALpEADgBcoIAMoSATgEsAdgHMQAXyJhBSEKkiZchEuRACqYAXW5EEdWDSojxUyLIUr1W8GzpDofXRsfCJSSAoBFnh4AAZGURBJaTklNU0fGjMcHAATFxAWPUV89zgs1xTPdKIJAE8xPGlcnFQNDSA>

 

from which the largest (and best, IMO) drive is this 320GB one:

 

<https://www.digikey.com/en/products/detail/atp-electronics-inc/AF320GSAJA-8BBIP/16537435>.

 

I own one of those, and it's the best SSD I've ever used.  I'll be buying more of these, for other builds.

 

I've seen that ATP also has a 640GB variant, according to

 

<https://www.atpinc.com/products/industrial-ssds-nvme-m.2-wide-temperature>

 

but I haven't seen that one available anywhere.  If we can show interest in these drives, maybe they get more easily available.  I suggested doing a video about it here:

 

 

[cmndr]

There's some enterprise solutions out there. I think some of the older dupastor drives are SLC (but they more recently moved to MLC, it's half the cost and 90+% of the benefit). Samsung did something with ZNAND as well. 
Optane is a fundamentally different technology from NAND (PCM) so I don't think SLC/MLC/TLC monickers apply though it's possible that it might technically be SLC. 

https://www.servethehome.com/dapustor-xlenstor2-x2900p-800gb-review-the-100-dwpd-next-gen-slc-optane-alternative-kioxia-intel-optane/

 

 

----
 

For what it's worth I have an OS installed on a 1.5TB optane drive on my personal system.
280GBish drives are also as low as $70 these days. 

IMO 280ish GB is enough for A LOT of use cases, including installing windows and a handful of key program. You'd definitely want another drive for things like files, games, and most applications though. 

[kokosnh]

54 minutes ago, cmndr said:

I don't think SLC/MLC/TLC monickers apply

it does apply. 

1 hour ago, cmndr said:

Optane is a fundamentally different technology from NAND

it's not, just addressing individual memory cells, instead of strings, and blocks.
It can be SLC, or MLC (TLC, QLC). 

"The advantage of 3D XPoint over NAND is mainly based on addressing (for read and write operations) of single cells instead of whole blocks, where, in order to perform a write operation, a whole sequence of read-modify-write operations has to be performed.

3D XPoint technology approach in which the memory cells are addressed individually and there are two physical connections available – one at the top and the other at the bottom of the 3D mesh – results in a technology that is ultra-fast and has benefits such as:

• Very low latency.
• Simultaneous read and write operations at very high speeds.
• Very high endurance without degradation of performance."
  
   

[cmndr]

1 hour ago, kokosnh said:

it does apply. 

I'll preface this with, "this is not in my usual wheelhouse" so I'm not a complete expert and information isn't as easy to source as I'd like... 

 

Humor me a bit. 
How does SLC terminology apply to Phase Change Memory? It's not really used as a marketing term and as far as I'm aware Optane has multiple bits stored per cell which would make it "MLC" if you were to apply those terms. 

 

https://en.wikipedia.org/wiki/Phase-change_memory

 

Quote

PCM also has the ability to achieve a number of distinct intermediary states, thereby having the ability to hold multiple bits in a single cell

 

[kokosnh]

So as far as I know (I mainly deal with NAND storage), there are SLC and TLC variants out there for optane (maybe there's more, and I'm just not aware of them), and I do not know if all SLC are pure, or pseudo ones. 

"3D XPoint uses different storage physics. Specifically, transistors are replaced by threshold switches as selectors in the memory cells. 3D XPoint developers indicate that it is based on changes in resistance of the bulk material"

soo as I understand it, in pure SLC they literally use just threshold switches, and in TLC , they measure resistance across it, to get analog data/response, that can be converted to multiple bits stored per cell.