MicroSD options, including MLC cards

Discussion in 'General Dash Cam Discussion' started by Deacon, Dec 20, 2016.

  1. Deacon

    Deacon Active Member

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    Conclusion (tl;dr)

    The only broadly viable MLC NAND options are the Transcend High Endurance line and the Kingston Industrial line, and now ADATA Premier Pro. Transcend gives a 2 year warranty while Kingston gives a 5 year warranty, both with capacities up to 64GB with plenty of speed for reasonable prices (https://www.amazon.com/gp/B01BDKTRAE for Transcend and https://www.amazon.com/gp/B01DOFCPNW for Kingston). Note that Transcend and Panasonic are the only ones who claim Error Correcting Code (ECC)! If 64GB is enough for you (or all you can use), and reliability is paramount over saving a few bucks, then definitely go for either the Transcend High Endurance or the Kingston Industrial, based on your personal preference between ECC and warranty period.

    I recommend the 64GB Transcend High Endurance microSD. If it works like it's supposed to, then you shouldn't need to exercise the warranty anyway.

    Otherwise, if your card won't see extreme temperatures and humidity (Alaska or Arizona or Houston), then PNY and Lexar both make 128GB+ microSD cards that aren't MLC, so they're cheaper per gigabyte, but they also don't void your lifetime warranty if used in dash cams. So if you want larger sizes, the Lexar High Performance 633x series (https://www.amazon.com/gp/B012PQKFNI) or PNY Elite series (https://www.amazon.com/gp/B01G26R7LA) make the most sense, available in larger sizes and fairly affordable. Sure, neither are MLC, but at least when your card dies you'll probably get a replacement.

    Of these, neither publishes temperature tolerance specs except for PNY's Elite Pro series which is way too expensive for what you get. So it's a toss-up if you don't want to buy the Transcend High Endurance like you should.

    Lexar 633x does not use MLC NAND despite rumors floating around the interwebs that all come from a single source or two who were purely speculating.


    Details

    Digging through a bunch of them, it appears many manufacturers are backing off MLC claims. Essentially if they brag about it as they should, then it's MLC. If they don't, it's TLC. If they claim they're mixed and can't guarantee it, then what they're guaranteeing is that none of it is MLC. No manufacturer is going to produce the much more expensive MLC and then toss it in the bargain bin with the TLC cards. It would be like a seafood provider choosing to mix in real high-dollar Deadliest Catch crab in with the imitation crab on purpose.

    Note that Transcend voids its lifetime warranty for cards used in in-car video recording devices. So if warranty means anything to you, skip the Ultimate line and go for the High Endurance line. Panasonic only provides a 1-year warranty anyway. PNY doesn't offer MLC, but they do claim a lifetime warranty without explicitly excluding dash cams. Lexar doesn't offer MLC, and their High Endurance line is only warranted for 2 years. Same for Sandisk's High Endurance for Video Monitoring line, 2 years.

    Clearly these manufacturers know how hard 1080p+ dash cams really are on cards, especially with the temperature extremes they see.

    Manufacturers

    Transcend definitely claims MLC with ECC for their high endurance line, basically the gold standard for dash cams, with a 2 year warranty and capacity up to 64GB: https://www.transcend-info.com/Products/No-727

    They also claim MLC for their Ultimate line which also tops out at 64GB, such as in this PDF where they say nothing about it for the Premium line, meaning TLC, but their lifetime warranty is void in dash cams regardless, and you don't need the extra speed, so stick to the High Endurance: https://www.transcend-info.com/products/images/modelpic/423/EN_microSD_ProductSheet.pdf

    Warranty: https://www.transcend-info.com/Warranty

    Kingston claims MLC for their Industrial line, but they don't claim any kind of ECC. Capacity only goes up to 64GB. They offer a 5 year warranty, and thankfully that warranty is not voided by use in a dash cam: http://www.kingston.com/us/flash/microsd_cards/sdcit

    Warranty: http://www.kingston.com/us/company/warranty

    ADATA claims MLC for their Premier Pro line. But no ECC. U3 speed up to 64GB. Lifetime warranty, apparently with no dashcam disqualifier. They're introducing 256GB 3D NAND cards soon, too, but for now this is their best option:
    http://www.adata.com/en/sd/feature/368

    Sony claims MLC for their SR-UZA series, even showing a 128GB model. But they don't claim ECC, nothing is available on their product or support web sites on the warranty, and the 128GB model doesn't appear for sale anywhere, making 64GB the largest actually available. Amazon indicates a 5 year warranty with no indication of limitations, and these cards are still twice as expensive compared to all but Panasonic, mostly because of the U3 speed. These cards are intended for professional photographers in extreme situations who are limited to the microSD form factor, and they're priced accordingly. Skip these and run Transcend High Endurance or Kingston Industrial for MLC offerings: http://www.sony.com/electronics/micro-sd-memory-cards/sr-uza-series

    Additionally, they appear to claim MLC for their "SR-UXA series" but with no mention of ECC nor of any warranty. The warranty PDF on Amazon states 1 year. If you have strong brand loyalty, I guess go for it? https://www.sony.net/Products/memorycard/en_us/4ksd/index.html

    Panasonic offers quite a few "Consumer Plus" SD and microSD MLC choices as an offshoot of their industrial lines, in this case the TE series specifically is the most appropriate. These are the real deal, and they include ECC. But they're only available in up to 64GB, only have a 1 year warranty, are tied with Sony for twice as expensive, mostly because of the U3 speed. These cards are intended for professional photographers in extreme situations who are limited to the microSD form factor, and they're priced accordingly. And they are not generally available on Amazon but instead only through Panasonic's own authorized resellers. Skip these and run Transcend High Endurance or Kingston Industrial for MLC offerings: https://na.industrial.panasonic.com/products/storage-media/sd-cards

    PNY doesn't claim MLC for any of their memory cards, but they do claim a lifetime warranty specifically for their High Performance and Pro Elite cards that have been "installed, maintained and operated under conditions of normal use and in accordance with the installation guide provided herewith." But they don't provide an installation guide and don't say what normal use is, and it's only applicable while that particular product being manufactured, so no "equivalent" replacements are promised. YMMV. http://www.pny.com/mega-consumer/shop-all-products/flash-memory-cards

    Warranty: http://www.pny.com/File Library/Sup...sh Memory Cards/Micro-SD-Warranty-Class10.pdf

    Lexar doesn't claim MLC for any of their cards, even their high endurance line. And they have a short warranty on those: http://www.lexar.com/products/memor...ndurance-microSDHC-microSDXC-UHS-I-cards.html

    That said, Lexar's High Performance 633x line, while not MLC, is available in higher capacities with a lifetime warranty that is not explicitly voided by use in dash cams which is nice: http://www.lexar.com/products/memor...nce-633x-microSDHC-microSDXC-UHS-I-cards.html

    Warranty: http://www.lexar.com/content/dam/DAM_Lexar/lexar-family/warranties/lexar-global-warranty.pdf

    Sandisk doesn't claim it for any memory card products, including high endurance lines, only some of their SSD's. They do have a special line for dashcams and surveillance systems, but they still void the warranty for dash cams: https://www.sandisk.com/home/memory-cards/microsd-cards/high-endurance-microsd

    DO NOT USE SANDISK ULTRA CARDS. It should go without saying at this point, but they're cheaper for a reason and have developed a very bad reputation in heavy use applications like dash cams.

    Warranty: https://www.sandisk.com/about/legal/warranty/warranty-united-states

    Samsung's marketing team originally claimed it when they released their current lines, then then said whoops sorry about that it's only for Pro and Pro+, and now they don't even claim it for those. And the warranty drops if you use it in any kind of surveillance device, saying in their full specs, "Warranty is limited for any type of surveillance system." So...not good: http://www.samsung.com/us/computing...ry_cards-microsd/_/n-10+11+hv22y+zq29p+trokt/

    However, they have introduced V-NAND microSD cards (EVO+ 256GB), which is very exciting. It's completely new fundamentally different from TLC/MLC/3D NAND and should in theory outlast MLC, and at higher capacities. They're still quite expensive, but could soon take over as the go-to card of choice for dash cams. http://www.samsung.com/us/computing...vo-256gb-memory-card-w-adapter-mb-mc256da-am/

    Toshiba doesn't claim MLC for any of their cards, and of course that means no ECC either. They offer a 5 year warranty, and that warranty says nothing about being void of used in dash cams: http://us.toshiba.com/storage/memory-cards/microsd-cards

    Warranty: http://cdgenp01.csd.toshiba.com/con..._warranty_storage_5_year_en_sp_bp_15may08.pdf for warranty.

    Delkin -- Stop using knock-off bargain brands in general, but especially in your dashcam. Stay away.
     

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    Last edited: Feb 17, 2017
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  2. DrekiTech

    DrekiTech Active Member

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    I'd heard the rumors about the Lexar 633x were MLC. Sad to see they are false and the cards are not MLC.


    Any info on the Toshiba Exceria line of cards? I couldn't find any definitive proof that they're MLC based, although the blurb on Toshiba's site seems to suggest they are. Specifically this line in their blurb: "Today, as one of the largest producers of MLC NAND Flash, Toshiba remains committed to supplying industry-leading densities and performance."
     
    Last edited: Dec 21, 2016
  3. reverend

    reverend Well-Known Member

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    The Lexar 633x cards are marketed in Korea as MLC - there were questions around the 128GB cards though as they had totally different performance characteristics which pointed to TLC (TLC had faster writes than MLC when I last looked).

    I've got a couple of the 64GB Lexar 633x cards which have been running for coming up close to 2 years now in a dashcam with constant parking mode running and they're still going fine.

    The accountants are always looking for ways to manufacture things cheaper though so there's always a chance an item changes spec throughout it's life - but they're still marketed as MLC in Korea.

    http://item2.gmarket.co.kr/English/detailview/item.aspx?goodscode=762361582

    Lexar don't like to seem to confirm either way what they use.

    I've only personally had one card toggle into read only mode and that was a cheap 4GB card that came free with a drone and died after a few uses.
     
  4. Deacon

    Deacon Active Member

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    That's a desperate reach by the marketing department if I've ever seen one. It would be like Ford saying as one of the largest producers of one ton trucks, we're proud to present the Fiesta hatchback.

    None of their offerings claim MLC, no ECC, 5 year warranty, and the warranty says nothing about being void of used in dash cams. I'll update the main post later but see http://us.toshiba.com/storage/memory-cards/microsd-cards for info and http://cdgenp01.csd.toshiba.com/con..._warranty_storage_5_year_en_sp_bp_15may08.pdf for warranty.



    No they're not. Your link was to an item on a Korean version of Alibaba, and the seller threw it into the title (after GoPro, but he's not selling a GoPro either). Maybe he fell for the web rumors, or maybe he's just unscrupulous or ignorant

    That should tell you everything you need to know.

    And seriously, even if you were holding onto hope, one thing that gives it away besides the speed is the massive capacity at low prices. 64GB U1 (at most) for everyone else at $50 to $100 is 200GB U3 at $70 for Lexar? Let's not kid ourselves. It doesn't appear anyone is making MLC microSD cards greater than 64GB. The only one I can find that claims it is Sony, but it appears to be vapor ware and would be massively expensive if it ever made an appearance.

    As with cars: fast, reliable, cheap. You can only pick two.

    Again, that's not to say it's bad quality or anything. Just not ECC MLC NAND and cannot be compared to it.
     
    Last edited: Dec 21, 2016
  5. reverend

    reverend Well-Known Member

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    At the time the Lexar 633x cards came out they were marketed as MLC in their own graphics and they definitely weren't $25 for 128GB - in the UK when they launched they were around $100 for the 64GB cards two years ago.

    Have you got definitive proof about the Lexar cards or is it just more speculation either way?

    I just want something that works and is reliable and so far the old Lexar 633x 64GB cards I have are exactly that - we had a lot of these same discussions almost two years ago here - https://dashcamtalk.com/forum/threads/mlc-microsd-cards.10294/

    You would expect Transcend to stand by their high endurance range with a longer than 2 year warranty though unless they don't want the money troubles of warranty replacements down the line coming back to bite them
     
    Last edited: Dec 21, 2016
  6. reverend

    reverend Well-Known Member

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    You may want to look at Delkin as well as they had some industrial offerings - don't know what happened to them though as there aren't many reports of people using them but they have some high capacity SLC offerings
     
  7. Nigel

    Nigel Well-Known Member

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    There seems to be an assumption that MLC is best? A few years ago it was, but maybe not anymore.

    If a 64GB Lexar 633x card is MLC and 128GB Lexar 633x card is TLC, which is the best? The 64GB maybe has a lifetime of 2x the writes per cell compared to the 128GB, but the 128GB has twice the cells so its lifetime in writes per card is identical. The difference then is only that the 128GB card keeps twice as much video before overwriting.

    I suspect that these days, Lexar may be selling 64GB 633x cards that are really 128GB cards but which have a bit not working so are configured to provide only 64GB. The wear levelling can then make use of the other 60GB spare cells to effectively double the lifespan in writes per cell and provide the same reliability as real MLC.

    Then there are new technologies such as Samsungs V-NAND where cells are stacked in a 3D matrix which has proved excellent for its SSDs and it is now using in its 256GB microSD cards. Not sure individual cells are necessarily more reliable but they can fit far more cells in including a lot of spare ones for the wear levelling to use so overall reliability is better than old MLC or even SLC that did not have wear levelling, and of course with 256GB you are not going to be writing to each cell very often compared to how often you would have to write with an old 8GB SLC card that is supposedly more reliable - the SLC would wear out first.
     
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  8. DT MI

    DT MI Well-Known Member

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    I can't comment on Delkin memory products but every Delkin product I've ever owned has failed miserably. As a result I won't even consider the brand for anything. YMMV.
     
  9. Deacon

    Deacon Active Member

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    Here's a whole bunch of stuff including my take on technology background and purchase considerations. I'm limited to 10,000 characters, so I can't add it to the original post. Is that something a mod can correct?

    I also added info on Toshiba cards and Delkin cards to the original post.

    Background

    MLC? TLC? SLC? What are these? Why should you care? Is one better than the other? ECC? What's with all the acronyms? Reference this handy chart from Panasonic:

    [​IMG]

    SLC came first. Each cell can have one of two states. It's simple, so it's inherently extremely reliable. But that's not a real option for dash cam users, because capacities are limited by physical form factor, and the prices are insane. An 8GB Panasonic SLC industrial card is too small and too expensive, the biggest they offer in a card fast enough to be of use, costing upwards of $130. The SLC benefits are negated in a dashcam application.

    MLC came next, where they were able to double the data per cell, and each cell can have one of four states. This is more complex and increases data density, so it's not as inherently reliable as the original SLC. But as a result it's way more affordable with a lot more options out there for it and at much higher capacities. At the time of this writing, a 64GB Transcend High Endurance card is sold by Amazon for $50.

    TLC came along more recently and is the current default NAND configuration for SD/microSD cards. It triples the amount of data per cell compared to the original SLC, and each cell can have one of eight states. This dramatically ramps up complexity which decreases reliability further, but it makes it a whole lot cheaper to produce, especially in high capacities.

    Remember that NAND flash memory actually does physically wear out over time. Every time you write to it, you're doing a tiny bit of damage to that cell. But while for SLC you're writing to the individual cell two to three times as often as in MLC or TLC respectively, the simpler the NAND cells, the easier it is for the controller to determine its state. SLC can have one of two states, so it's super simple, which means the controller can easily determine its state. By the time it's "too damaged" to work, it's been written to many more times than the others. MLC can have one of four states, so it doubles the difficulty of the controller to determine its state, but one out of four ain't bad, so it's still good. TLC can have one of eight states, so it doubles the difficulty again compared to MLC (cubes it vs SLC!) for the controller to determine its state. So because the controller has to look so closely to determine its state, the cells can become "too damaged" a whole lot faster (after fewer writes).

    So for dashcam use, where reliability is paramount because it's a worthless device if it's not recording the incident that just happened, MLC is currently the best choice. However, there are more considerations beyond that.

    Controllers

    Storage is worthless without a controller. Yes, those tiny cards have a controller built in to determine how and where data is being written to and read from within the physical NAND chips. The better and more reliable the controller, the better able it is to read the cells for longer, increasing the working lifespan of the card. In addition, only a couple support Error Correcting Code, which is a sophisticated function that detect and correct internal data corruption. This is something often reserved for industrial/enterprise use (some may be familiar with it from recommended enterprise server computer RAM), but it's available in both Transcend High Endurance and Panasonic Consumer Plus microSD cards. That theoretically makes those two cards the most reliable the MLC choices for dashcam use.

    But then there are other considerations like how the data is written to the card. The best controllers will spread out write operations uniformly across the cells, balancing the tiny bit of damage done to each cell among the whole chip so that none wear out faster than the others. Unfortunately, none of the manufacturers specify whether they do that and for which products, so while it's an interesting concept to be aware of, it doesn't help us choose.

    Speed

    There's also speed to consider, but realistically any Class 10 card will be plenty for today's dashcams that record in up to 1440p. Beyond Class 10 there are U1 (faster) and U3 (way faster) standards, with most Class 10 MLC cards today being U1 rated and a couple U3. If you're paying extra for U1 or U3, you're wasting your money, as that's intended for super high resolution DSLR cameras shooting in burst mode and giving plenty of headroom for 4K recording. A high quality 1080p30 camera with low levels of video compression will generally write about 15Mbits/second, which is only 1.875MBytes/second. So Class 10 is already plenty fast enough. Being able to write at 80MB/s is a complete waste. It doesn't hurt anything other than your wallet in some cases, but it adds no value at all. For reference, Transcend High Endurance are Class 10 cards with 20MB/s write speed while Kingston Industrial are U1 cards with 45MB/s write. That means both are overkill when it comes to speed, so you're good to go with either one.

    Size

    Another major consideration is size. Some dashcams top at out 64GB, for example, so be aware of that before you buy. And of course the bigger the card, the more it costs. But it's not just that. The bigger the card, the more NAND cells there are to write to, which means each cell gets written to less often, which means the working lifespan of the card will be extended. So a 32GB Transcend High Endurance card is $17.99 on Amazon right now while the 64GB version is $49.99. So you're paying a little more more per gigabyte, but you're also effective doubling the expected lifespan of a card that's already the gold standard. Spend once, cry once.

    For non-MLC (aka TLC) and non-ECC cards, though, size becomes very important for reliability. If you're going that route, get as big a card as your camera supports and as makes reasonable monetary sense. For example right now the Lexar 633x 128GB is $36.99 while the $200GB version is $69.95, right about twice as much. If you can afford it, go ahead and nab the 200GB version if your camera supports it. They have a 256GB version, but it's $275! Not at all worth it for that extra 56GB.

    But really, just get the Transcend High Endurance 64GB and call it a day.

    Temperature

    MLC cards will list temperature specs, with a handful of TLC cards listing them (usually the ones with names like Pro or something in the name). If you live in San Francisco, it's probably never going to get cold enough or hot enough to matter, even "baking" in the car on the sunniest and hottest day of the year. But if you live in Nebraska or New Mexico, however, you may be dealing with extremes in one direction or the other or both. Quality cards will list temperature maxes of -25C (-13F) to 85C (185F). That should be sufficient for most of us. If it's not listed, it doesn't mean it will automatically die parked in the roasting sun of a Phoenix summer or overnight in the shattering chill of a Bismark winter. Hopefully, though, if you're driving in those fairly extreme climates you can remote start your car to cool it down or warm it up a little before actually pulling away, though hopefully it'll cool down or warm up quickly while you're in the car regardless, right? :) Otherwise, get the highest quality card like the Transcend High Endurance and just run it until it eventually has a problem, which will probably be a long time into the future.

    Warranty

    If you have to use the warranty, that's not good, because the card failed, hopefully not when it counted. But many manufacturers void the warranty entirely if you ever use it in a dash cam. That's because a writing over and over again to the card in a loop like dashcams do naturally accelerates the rate at which you're doing damage to the card. The manufacturers know this and warrant accordingly. High Endurance lines generally have a shortened 2-year warranty, though Kingston does offer 5 years for theirs. Panasonic only covers it for 12 months! See references below for each manufacturer and check the warranty carefully just in case you ever have to use it.

    Vendor

    The last major consideration is who you buy from. Buy directly from Amazon, a manufacturer authorized online reseller in your country, or a reputable local brick and mortar place like Best Buy. Do not buy from some other seller who has their stuff listed on Amazon or even fulfilled by Amazon. If you're buying on Amazon, make sure you choose the option where it's SOLD BY Amazon only. Why? Counterfeits are rampant. Cheap crap is being passed off as high end, high capacity cards, including in capacities and speeds never even claimed by the manufacturer! Don't try to save a few bucks by rolling the dice on what could be counterfeit cards. Avoid eBay, Alibaba, and third party sellers on Amazon.
     
    Last edited: Dec 22, 2016
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  10. Deacon

    Deacon Active Member

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    It 100% still is. It's known good versus unknown might be good might not.

    It's not. None of the Lexar cards are MLC. If they did release a new 64GB MLC card, though, which they haven't, that would be the recommendation over the 128GB TLC card. But the real recommendation would still be Transcend High Endurance for MLC with ECC and published temperature specifications at a reasonable price.

    Your math is all wrong comparing a 64GB MLC card to a 128GB TLC card. Reference my post above if you're unclear about MLC vs TLC.

    They claim no such thing, never have. And they'd only be shooting themselves in the foot doing so. Your logic is derailed because TLC and MLC are physically different. Disabling a bit in TLC would just be giving up capacity for no gain.

    Citation needed.

    That's not how this works. That's not how any of this works.
     
  11. Nigel

    Nigel Well-Known Member

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    Your posts are looking like an advert for "Transcend High Endurance" !
    Does this satisfy you?
    https://news.samsung.com/global/sam...d-card-with-the-highest-capacity-in-its-class

    Here is a review of it confirming the high speed performace of the Samsung Evo+ and confirming that it is not conventional TLC or MLC : http://www.techspot.com/review/1207-samsung-evo-256gb-microsd/
     
    Last edited: Dec 21, 2016
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  12. Nigel

    Nigel Well-Known Member

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    Unfortunately, it is actually unknown versus unknown, since MLC today has very different reliability to MLC from a few years ago. As they pack more memory into the same space in order to either increase capacity or reduce cost, the memory cells have become smaller and as the reliability and lifetime of the cell depends heavily on the size of the cell, the memory, both MLC and TLC, has become less reliable. The loss of reliability has been partly made up for by better wear levelling and error correction which can map spare cells in to take the place of failed cells.
     
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  13. Deacon

    Deacon Active Member

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    Haha yeah, I guess I can see that. I have absolutely nothing whatsoever to with Transcend or anyone who sells or profits of Transcend or any other manufacturer or anything like that. It's not intended to be promoting Transcend. It's just that right now, whatever category you look at, it all comes back around to their High Endurance line. It's the sweet spot with the highest reliability at the lowest price available in the largest capacity of its class. And it's not purely because of MLC and ECC. More details at the end under the manufacturing bit.

    It's not a question of satisfying me. It's a question of backing up statements made in what is intended (at least by me) to be a facts-only zone. Samsung's V-NAND is very interesting. If they can manage to manufacture it at high enough scales to allow prices to fall, and if the manufacturing process proves to be consistent enough, then they may take over the flash memory market. It's been a few years since they announced it, so it's nice to see it finally coming to to microSD cards instead of only enterprise SSD offerings.

    Samsung's V-NAND is a type of 3D nand that is quite different in execution from standard 2D planar NAND. One of the major benefits for dash cam use, at least in theory, is that the physical wear that occurs in planar NAND should be reduced as well as the consequences of that damage being lessened. Meaning that as long as temperatures or some other such factors don't cause a premature death, its charge trap approach should allow it to have a far longer lifespan.

    Note that the card is still $200, and while you can apparently pick them up at Best Buy they're not universally available. And we have yet to see them proved out in the rigors of a dashcam environment. But it's still exciting nonetheless. Also note that while hey offer a 10 year warranty, they seem to stick to "limiting" their warranty when used in any kind of surveillance system. I have a feeling they'll release an "industrial" or "high endurance" or "EVO+ Pro Elite Platinum" or whatever that will basically be the same card but with only the cleanest yields of their production runs and charge a premium for it, without sacrificing the warranty. If so, they could take over as a leading option as prices fall and dashcam resolution gets higher.


    One note about manufacturing, in general, is that while it's a repeatable process, each run can produce varying degrees of successful results. In the computer processor space, for example, it's very common for manufacturers like Intel and AMD to crank through a production run and then test their yields. Those that test well get blessed with higher clock rates. Those that don't get sold as lesser clock rates. Sometimes you hear about a certain run of CPUs being very overclocker friendly. That's usually because the runs have produced high yields with great results (especially when it's a manufacturing process they've already worked all the kinks out of), but there's still plenty of demand for lower clocked units and they won't want to step on the perceived value (higher sales price) of the higher clocked units. So a unit that is perfectly capable of a given clock rate is essentially underclocked when it goes out the door. If someone tries to overclock it, they can be quite pleased with the results (assuming the motherboard and RAM and such can all keep up).

    When it comes to NAND, it can be very similar. With constantly shrinking dies, they can not only increase bit density through making each cell a 3-bit cell, but each cell itself is that much smaller, allowing them to fit more of those 3-bit cells in the same space. Some production runs come out beautiful, but others fall prey to manufacturing defects, with inconsistencies or straight up bad cells right out of the gate. (It's sort of like how you never wanted to low-level format platter hard drives because they all had bad clusters that were found and marked by the factory so nothing was ever written there.) One possible result is that the good chips are put in cards advertised as greater capacity, while those that fall below a given threshold are sold as cheap "value" cards or sold off entirely for use in markets and products that don't require much in the way of repeated writing or high capacity. An example might be a toy that plays certain music or sound or kiosks/displays with a relatively small file size looping video that plays all day, since reading isn't so destructive like writing. I suspect this may be where counterfeit cards come in, taking those factory seconds and dressing them up in housings that look like the real deal, but they can't (and aren't intended to) match the performance and reliability of the real deal.

    But for "high endurance" type offerings, they shouldn't just take the best chips. They are supposed to be specifically manufacturing them with thicker layers and even better use less dense formats (like MLC instead of TLC) and even better use controllers with ECC capabilities. That means they can take more write hits before the gate layers are worn out, their charge state can be detected through relatively tattered cells, and they can find errors and correct them before widespread data corruption sets in or they throw in the towel or raise the white flag or whatever metaphor you prefer for giving up and declaring themselves too riddled with errors to continue. And it's because of all those considerations that right now you can't reliably find High Endurance MLC ECC NAND in a microSD form factor in capacities higher than 64GB.

    If it sounds like I'm shilling for Transcend, it's because right now they're the only ones offering High Endurance MLC NAND with ECC at 64GB for a reasonable price. Panasonic is the only one I've found that offers it at all, but theirs is twice the price with half the warranty.
     
  14. Deacon

    Deacon Active Member

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    Citation needed for all that bolded stuff.
     
  15. reverend

    reverend Well-Known Member

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    Deacon you've got assumptions in your posts so some citation needed there too - it works both ways ;)

    It's definitely good to get consumers steered in the right direction with these posts though :) Transcend did have an issue with quite a lot of the Ultimate cards on here at one point where they were toggling to read only - I haven't been around here much the past year so hopefully that's died down.

    Transcend also have SuperMLC cards although that's potentially overkill for dashcam usage - https://us.transcend-info.com/About/press/11113

    That Samsung V-NAND stuff is interesting Nigel - I didn't realise they'd shrunk it down to microSD size yet - I'm running one of the Evo+ 128GB cards in a RetroPie setup and it has worked well to date but guessing that's TLC
     
  16. Deacon

    Deacon Active Member

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    Assumptions like what? :)

    I'm not sure why people are linking to press releases, which generally aren't very useful and puts the burden on everyone else to figure out how to get useful info on it. Here's a product page for an industrial temp Transcend MLC ECC 64GB microSD for those who live in extreme cold and need tolerances down to -40 degrees: https://us.transcend-info.com/Embedded/Products/No-574

    Still a two year warranty. It's not widely available, but it appears you could special order it through CDW for about $65: https://m.cdw.com/shop/products/Transcend-Industrial-Temp-flash-memory-card-64-GB-microSDXC/3891618

    Only reason I could see using it for dashcam purposes is for those who live in the arctic and want to be extra super sure it won't freeze on them.

    The SuperMLC stuff is unnecessarily fast and expensive and only goes up to 32GB and still only has a two year warranty: https://us.transcend-info.com/Embedded/Products/No-739

    Also appears on CDW's site in 32GB for about the same $65, but the availability says "Call" which doesn't sound promising: https://m.cdw.com/shop/products/Tra...DHC220I-flash-memory-card-32-GB-micro/4133583
     
  17. Nigel

    Nigel Well-Known Member

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    Yes, this isn't Wikipedia, we don't insist that every fact is accompanied by a citation :)

    Instead we learn to trust/distrust as appropriate the other members of the community.

    I'm not sure what is in the smaller Evo+ cards, whatever it is is certainly different to the previous Evo cards. I wouldn't be surprised if it is actually a version of V-NAND but without the highly parallel write access that gives the high performance of their 256GB and the SSD drives. Using a 48 layer V-NAND would mean they could get 48x more microSD cards from 1 silicon wafer, and that would mean big profits!

    I guess you are referring to my link to a Samsung press release on the Samsung web site? Fact is, that is the most detailed information they give out, everything else they keep secret and is not available elsewhere. Some companies do give out more information, but it is often out of date, or becomes out of date soon after release.
    Maybe that only Transcend use ECC error detection? I think all decent modern SD cards use some form of error detection and as cell size has reduced it has become increasingly important to be able to map spare cells into the place of bad/worn out cells without corrupting any data in the process, you can't do that unless you can detect and correct errors in the storage.
     
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  18. Deacon

    Deacon Active Member

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    We can only go by manufacturer claims. Everything else is an assumption. Lexar does not claim MLC for the 633x line, for example, so we do not assume it's MLC. In that vein, I do not assume that only Transcend provides ECC on an MLC card with sufficient speed and capacity at a reasonable price. Instead, it is a fact that no other manufacturer (so far) makes that claim.

    And while this isn't Wikipedia, there have been speculation and rumors, both stated as though they were facts, not just online in general but in both this thread and in the "My in-depth video guides..." thread that inspired this one. So when someone comes in and makes statements like Samsung is using V-NAND for the first time ever in microSD cards and are available in 256GB sizes, it would be much appreciated if it weren't just something tossed out there as an assumption of fact but to be accompanied with a link or two of supporting evidence and with more info for the interested. Without that, it's up to everyone else not only to make an assumption regarding whether it's fact or fiction, but also to individually duplicate each other's efforts in searching out that information.

    I sank many hours into ferreting out this information and have been meticulous about providing links as much as possible to all the info so interested people can go find out what I did without duplicating all that effort. It would be nice when someone comes along and throws out what could be exciting new information or more internet speculation would at least provide a single link for it.

    So especially when you come in and say something as potentially major and yet still a little vague like, "MLC today has very different reliability to MLC from a few years ago," some indication that this is fact rather than just your own personal musings would be nice.
     
    Last edited: Dec 22, 2016
  19. jokiin

    jokiin Well-Known Member Manufacturer

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    you've mentioned a few times that the Transcend High Endurance cards have ECC, we use the Transcend 400x cards in our products and it's probably worth pointing out that they also have ECC https://www.transcend-info.com/Products/No-423

    the Transcend cards have proven to be more reliable than other brands we have used previously, certainly a good choice particularly for any Novatek based camera models
     
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  20. Deacon

    Deacon Active Member

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    Thanks for sharing! A dashcam manufacturer's experience is valuable. The 400x are good cards for those looking to save a few bucks, as you get a quality card at an affordable price. But their lifetime warranty is void the moment you put it in your dash cam, and it's TLC planar NAND with no provision for endurance. ECC is a fantastic feature, but I'd rather start with an inherently more reliable design and then add ECC to that.

    Yeah, I know, you can get a 128GB Transcend 400x for the same price as their 64GB High Endurance. If you went the 400x route I'd definitely recommend going for the larger capacity. But for the same money I'd rather have the 64GB MLC high endurance option. I want my dashcam to be as set and forget as it can possibly be, and the extra peace of mind would be worth having "only" about 10 hours of video on the card. And if for some reason over the next couple of years I ever have a problem, I know there will be no trouble with the warranty. I have a feeling it wouldn't be hard to get one of their 400x (or 633x) cards replaced under warranty, either. But I'm a believer in using the right tool for the job.

    I'm really hoping Samsung's V-NAND microSD cards end up being as solid and long-lived in practice as they should be in theory. That would mean a fantastic new option with massive capacity and inherent endurance and more speed than you could possibly need in any dashcam for the foreseeable future.

    By the way, if anyone knows of any other options for High Endurance MLC NAND with ECC at 64GB for a reasonable price, I'd love to add it to the list. I can't seem to find anything other than Transcend.
     
    Last edited: Dec 23, 2016
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