2-bit MLC vs 3-bit MLC (TLC)

[GamerBlake]

What is the difference between an SSD that has 2-bit MLC (SLC) such as the Samsung 970 Pro and an SSD that has 3- bit MLC (TLC) such as the Samsung 970 EVO Plus?

 

Is it worth all the extra money to go for SLC over TLC?

[Mateyyy]

Whether going with a 970 Pro that uses MLC NAND as opposed to TLC (like the 970 Evo) is worth it or not depends on what you plan on doing with said drive.

 

I'm just going to take a guess and say it's not worth it in your case.

[Jurrunio]

In theory, durability and performance (random read writes I think, not sustained read writes) is better on MLC

 

In practice, if you dont have a stopwatch or stare at transfer rate, you wont be able to spot the difference. Not worth it if you ask me

[WereCat]

MLC can endure more write cycles than TLC. 

 

As for the SAMSUG marketing terms... 2-bit MLC is MLC, not SLC. 

SLC is 1-bit per cell and TLC is 3-bits per cell. 

Technically the "M" in "MLC" stands for "Multi" so they are abusing the marketing terms because "TLC (3-bit) or QLC (4-bit) are also technically multi (2+)" but nobody in their right mind is going to call TLC or QLC a MLC with x-bit.

[GamerBlake]

25 minutes ago, Mateyyy said:

Whether going with a 970 Pro that uses MLC NAND as opposed to TLC (like the 970 Evo) is worth it or not depends on what you plan on doing with said drive.

 

I'm just going to take a guess and say it's not worth it in your case.

Well I’m just going to be gaming and I have about 800GB left on my 2TB Samsung 860 EVO SSD and about 500GB available on my Samsung 970 EVO Plus NVMe SSD but because I keep my entire Steam library on my computer that space will fill up fast.

 

Usually I put my least demanding games (like Starcraft, Diablo, etc.,) on my 2TB Seagate Firecuda SSHD.

 

Then I put older, but more demanding games for that time (like Resident Evil 7, Metro Exodus, etc.,) on my 860 EVOs.

 

Lastly I put newer, very demanding games (like Red Dead Redemption 2, Assassin’s Creed: Odyssey, Cyberpunk 2077 etc.,) on my NVMe SSD.
 

But my 970 EVO Plus can only hold a few more games so I was thinking or adding either a 2TB 970 EVO Plus NVMe or a 1TB 970 Pro since both are the same price range. But if I won’t get any real benefit from the 970 Pro I might as well get 2x as much storage space for the same price with a 970 EVO Plus.

[Mateyyy]

2 minutes ago, GamerBlake said:

-snip-

A QLC SSD would work just as well for games, like a Crucial P1 or Intel 660p. Going with MLC for a games drive is frankly just plain stupid.

[GamerBlake]

19 minutes ago, WereCat said:

MLC can endure more write cycles than TLC. 

 

As for the SAMSUG marketing terms... 2-bit MLC is MLC, not SLC. 

SLC is 1-bit per cell and TLC is 3-bits per cell. 

Technically the "M" in "MLC" stands for "Multi" so they are abusing the marketing terms because "TLC (3-bit) or QLC (4-bit) are also technically multi (2+)" but nobody in their right mind is going to call TLC or QLC a MLC with x-bit.

So I’m guessing the 970 Pro is for people who move large amounts of data around often and need that extra endurance of many many read & write cycles?

[GamerBlake]

Just now, Mateyyy said:

A QLC SSD would work just as well for games, like a Crucial P1 or Intel 660p. Going with MLC for a games drive is frankly just plain stupid.

I do have a QLC drive with my 1TB Samsung 860 QVO and it does seem to load games and maps and stuff just as quickly as my more expensive 860 EVOs.

[mariushm]

To be 100% accurate. it's erase cycles, not write cycles. 

Memory is arranged in small blocks of let's say 4 KB, and then you have a bunch of blocks arranged in pages, typically 512 KB in size. You can write any block in a page, but you can't overwrite it. To overwrite a block, you need to erase the whole page, so the contents of the blocks you don't want lost needs to be copied and written in other pages whenever a page has to be erased. 

SLC supports up to 10-20k erase cycles, MLC supports up to 6-10k, TLC goes down to 2-4k, QLC goes down to around 600-1000 erase cycles. 

 

So MLC gives you a lot more endurance, meaning the maker can give longer warranty, higher number for TBW (terrabytes written over the ssd life) and in theory you can also get higher write speeds.

I say in theory higher write speeds, because these days most ssd controllers can switch a portion of the flash memory into pseudo-SLC mode, where they store only 1 bit instead of 2 or 3 in each cell, which gives those pseudo-SLC pages a much higher endurance (3-5x more erases I would guess) and much faster writes, so basically you could have faster speeds with a TLC drive that uses pseuso-SLC mode, compared to an older MLC drive that was made with a controller that has no such feature. 

 

 

[mariushm]

Just now, GamerBlake said:

So I’m guessing the 970 Pro is for people who move large amounts of data around often and need that extra endurance of many many read & write cycles?

It would be better for high IOPS stuff and lower latency stuff, like constantly updating a big database, with big transaction logs, or serving lots of content (thumbnails, various things), or for example with software that renders huge things by streaming textures from the SSD constantly. 

 

Just now, GamerBlake said:

I do have a QLC drive with my 1TB Samsung 860 QVO and it does seem to load games and maps and stuff just as quickly as my more expensive 860 EVOs.

Games write very little on a drive, they mostly read game files, extract what they need, optionally uncompress and load in video card ... most of this is done in ram, the ssd just reads the file and that's all. 

A QLC drive will be fast enough at reading to not matter that much. 

 

 

[VeganJoy]

10 hours ago, mariushm said:

I say in theory higher write speeds, because these days most ssd controllers can switch a portion of the flash memory into pseudo-SLC mode, where they store only 1 bit instead of 2 or 3 in each cell, which gives those pseudo-SLC pages a much higher endurance (3-5x more erases I would guess) and much faster writes, so basically you could have faster speeds with a TLC drive that uses pseuso-SLC mode, compared to an older MLC drive that was made with a controller that has no such feature. 

ah thats interesting, and im assuming thats how drives like the corsair mp510 and many of the phison e16 pcie 4.0 drives have 1800 TBW ratings?

[ewitte]

16 hours ago, VeganJoy said:

ah thats interesting, and im assuming thats how drives like the corsair mp510 and many of the phison e16 pcie 4.0 drives have 1800 TBW ratings?

I don't see an issue as a lot of tests show decent drives can typically handle petabytes.  The ratings are for warranty and product segmentation mostly at this point.

[ewitte]

On 10/27/2020 at 1:46 AM, mariushm said:

I say in theory higher write speeds, because these days most ssd controllers can switch a portion of the flash memory into pseudo-SLC mode, where they store only 1 bit instead of 2 or 3 in each cell, which gives those pseudo-SLC pages a much higher endurance (3-5x more erases I would guess) and much faster writes, so basically you could have faster speeds with a TLC drive that uses pseuso-SLC mode, compared to an older MLC drive that was made with a controller that has no such feature. 

 

 

The 1TB 980 pro can allocate as much as 114GB of SLC Cache they increased it many times over the 970 evo + drives.

[Doobeedoo]

Sadly SLC and MLC is dead now. 

[SavageNeo]

On 10/28/2020 at 12:15 PM, ewitte said:

The 1TB 980 pro can allocate as much as 114GB of SLC

it is not SLC, it is TLC, 970 pro has better technology than 980 pro: MLC.

 

According to our ssd god Vexicus, SLC is pretty dead since it is expensive to makie etc. MLC is dying too. TLC is the new thing. IT is slower than slc, or mlc, but can handle more petabytes of files and is more reliable.

[ewitte]

3 minutes ago, SavageNeo said:

it is not SLC, it is TLC, 970 pro has better technology than 980 pro: MLC.

 

According to our ssd god Vexicus, SLC is pretty dead since it is expensive to makie etc. MLC is dying too. TLC is the new thing. IT is slower than slc, or mlc, but can handle more petabytes of files and is more reliable.

"SLC Like" I left off a word.  Essentially just a portion that uses 1bit per cell the minimum is 6GB and maximum is 114GB on the 980PRO.  Which is a considerable amount over the 970 evo plus.