TLC/MLC. Samsung 840 Evo OR Toshiba Q Series SSD, Total Bytes Written, help

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citizens3

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Oct 10, 2013
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Hey all, I have both 250GB and 256GB drives of Samsung 840 Evo and the Toshiba Q Series. I'm going to have to return one and wanted to know which one to return? You might say the Toshiba but I still had one concern with the Evo...

I know that the Evo is TLC and the Toshiba is MLC flash. Even so, I was going to keep the Evo but after restoring a clean image (a second time) the "Total Bytes Written" on the Samsung Magician Software went from 0.06TB to 0.16TB.

Endurance testing on the 840 TLC shows it goes up to 242TB of writes. I'm already at 0.16TB, I can picture this number going up with large transfers to/from my external storage.

Should I be concerned and instead keep the Toshiba?
 
Solution
gorskiegangsta
Endurance testing for TLC was carried out on a 120GB Samsung 840 models with a fairly conservative (i.e. worst case scenario) ~250TB validation. For larger capacities, drive endurance should scale linearly. Why? Because it is the same number of program erase cycles but for higher capacity. So that'd be ~500TB, conservative, for the ~250GB models.

0.16TB is 160GB. Taking those TLC validation numbers into account, even if you write 160GB/day, every day, to the drive, it'll still take you 3100+ days (about 8.5 yrs) to completely wear out the drive. That said, it is important to remember, in addition to this being wildly unrealistic use case:
a. Since they're the ones that manufacture it, Samsung only picks the highest quality NAND for...
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gorskiegangsta

gorskiegangsta

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Endurance testing for TLC was carried out on a 120GB Samsung 840 models with a fairly conservative (i.e. worst case scenario) ~250TB validation. For larger capacities, drive endurance should scale linearly. Why? Because it is the same number of program erase cycles but for higher capacity. So that'd be ~500TB, conservative, for the ~250GB models.

0.16TB is 160GB. Taking those TLC validation numbers into account, even if you write 160GB/day, every day, to the drive, it'll still take you 3100+ days (about 8.5 yrs) to completely wear out the drive. That said, it is important to remember, in addition to this being wildly unrealistic use case:
a. Since they're the ones that manufacture it, Samsung only picks the highest quality NAND for their SSDs - that goes for 840 "basic" and EVO as well as the Pro.
b. Samsung employs ASP (advanced signal processing) in their SSDs which prolongs their lifespan by having their complex controller algorithms adjust the NAND for being more intelligently overwritten, and do on the fly error correction (ECC).
c. The 840 "basic" and EVO models have reserved spare area on them, which is used for replacement of bad blocks, should those ever occur, which further prolongs the lifespan of the drive.

So, the question you have to ask yourself, do you plan to regularly write large (i.e. hundreds of GB/day) amounts of data to your drive? Obviously, the initial OS/data transfer doesn't count, since it is more or less a one time thing. If the answer is "no", I wouldn't give it a second thought and just stick with the EVO.
 
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Akashdeep

Akashdeep

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Simply keep the Samsung one, and return the Toshiba.

In regards of SSD, Samsung beats all.
 
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citizens3

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Thanks for that. I guess the Toshiba will have to go. I don't think it was bad or unreliable by any means, but it didn't have any SSD monitoring software or firmware updates like the Samsung. It probably doesn't need any updates, and its MLC integration is reliable in itself.

Performance wise, the only difference I've noticed is that the Samsung showed higher 4K numbers on Crystaldiskmark on both read and write.

Only issue left is Samsung's Turbowrite buffer technology on the 840 Evo. If I'm writing a file larger than 3GB, then the write speeds are going to decrease from the 500s to the 200s, whereas the Toshiba's won't change regardless of size.

Ah, what a confusing thought process...
 
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hmsathawane

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Endurance of MLC is much higher (3k write cycles) than TLC (few hundred write cycles) no matter which company's NAND you buy. TBW number is directly proportional to the write endurance. If the MLC based SSD price is not too high, I'd keep the MLC drive.
 
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gorskiegangsta

gorskiegangsta

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TLC (3 bit per cell) NAND is able to withstand anywhere between 1,000-3,000 PE (program erase) cycles, MLC (2 bit per cell) is anywhere between 3,000-10,000, and SLC is anywhere between 10,000-30,000. Those were often conservatively rounded down in the past because SSD controllers, and the underlining write algorithms, were relatively new and thus weren't the best they could be, which isn't really the case anymore. Today, a high quality TLC SSD (e.g. 840 EVO) can effectively withstand 3000 PE cycles due to Samsung strict binning process and technologies like ASP (advanced signal processing). There were a couple of endurance tests which showed the 120GB 840 (old model) consistently withstanding anywhere between 3000-3200 PE cycles, showing the first error after anywhere between 350-600 TiB of writes, which is way above what most consumer (even prosumer) users will write over the life of the drive.
 
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autumn_suns3t

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No, gorskiegangsta, the question he had to ask himself was another one:
1) Considering MLC memory is largely superior to TLC, and Toshiba doesn't cost more than Samsung, do I have ANY reason in the world to choose Samsung?

As I like to question myself a lot about everything, I also asked myself the possible reasons for your zeal in advertising Samsung :))

As for the "Samsung beats them all" one, steady state benchmarks, the only ones to truthfully show SSDs performance, and the most rarely performed by review sites as they aren't liked by companies, show that quite a lot of brands are more serious than Samsung (Mushkin, OCZ, Intel, Toshiba, Corsair even if it's not an OEM, and above all SanDisk): if there is one who beats them all, that is SanDisk, with OCZ/Toshiba closely following.
 
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