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My experience: 1) All microSD cards have a high failure rate. 2) Cheap cards sourced directly from China are usually fake and will fail a format test. I tried

My experience: 1) All microSD cards have a high failure rate. 2) Cheap cards sourced directly from China are usually fake and will fail a format test. I tried multiple times and could never find a reliable source. 3) MS Bitlocker is a security measure that also seems to serve as a reliability test. Cards with physical memory reliability issues seem more prone to write failures with Bitlocker. It's better to know about this up front. 4) If your data is really important, always make a backup copy of any card. 5) Physically, microSD cards are fairly durable and even water resistant thanks to being encased in epoxy. I have one on my watch strap and take it wherever I go, even the shower and pool. Just make sure it is dry before plugging it in. https://www.thingiverse.com/thing:6784665 https://www.thingiverse.com/thing:6784665

matsemann 2y ago
Ref 2: if you buy from Amazon, you never know if you get a genuine card. Even if you shop from an official seller, as inventory is commingled so you might as well get a fake one from another seller with the same SKU. Big problem in action cam related circles, where lots of people have broken recordings due to fake cards.
- everybodyknows 2y ago
  Are you saying that the counterfeiting of name brand packaging is so skillful that even careful inspection by us the consumers cannot reasonably hope to detect it?
  - AlexandrB 2y ago
    Unless you have the real and the fake side by side it can be really hard.
    - dboreham 2y ago
      Even then it's hard because the legit vendors change their packaging frequently.
  - cwillu 2y ago
    https://www.bunniestudios.com/blog/on-microsd-problems/ https://www.bunniestudios.com/blog/on-microsd-problems/ “One vendor in particular interested me; it was literally a mom, pop and one young child sitting in a small stall of the mobile phone market, and they were busily slapping dozens of non-Kingston marked cards into Kingston retail packaging. They had no desire to sell to me, but I was persistent; this card interested me in particular because it also had the broken “D” logo but no Kingston marking.”
  - Forgeties79 2y ago
    Yes it’s a very big problem until you run speed tests and the like which most people have no clue how to do.
- jqpabc123 2y ago
  if you buy from Amazon, you never know if you get a genuine card. Yes, but there is a significant difference --- I can always return it to Amazon postage free if the capacity is fake and it won't format properly. Presumably, Amazon extracts the appropriate weight in flesh from the seller. The way retail typically works in the USA, the vendor assumes all the risk --- any problems get unrolled backwards. You can sell a fake product on Amazon --- but it will likely cost you --- not Amazon (who controls the money) nor the end consumer if he is astute. Basically, Amazon acts like an escrow service.
  - Palomides 2y ago
    you're still feeding the machine, and assuming you can catch cases where something is merely lower quality rather than completely fake
    - jqpabc123 2y ago
      If there are too many returns, the machine doesn't get fed; it gets punished. Amazon and other retailers have played this game for a very long time and they aren't in it to lose money. In my experience, the thing most commonly faked with memory cards is the capacity --- for example, an 8Gb card altered to appear 64Gb, until it is formatted. If you want extra assurance, buy Amazon branded cards. In this case, Amazon assumes almost all the risk so there is little incentive for fakery.
      - Forgeties79 2y ago
        > If there are too many returns, the machine doesn't get fed; it gets punished. On Amazon? I highly doubt it. The threshold for “too many returns” is probably rarely hit. MicroSD’s are super cheap - people don’t return things that are cheap because they don’t consider it worth their time. Then these companies go and pay people for good reviews and just keep flipping inconsistent/garbage products. If punishment were a real thing that companies had to deal with then this wouldn’t continue to be a problem. It’s been this way for many, many years. Amazon has no equal competitor, there’s nowhere else for folks to go and people rarely look at the specific vendor they’re buying from. As far as they’re concerned it’s all Amazon.
- mikae1 2y ago
  First rule: never buy flash storage from Amazon.
- lazide 2y ago
  Personally I found an easy way to tell - write a script which fills the drive fully with random data (computing a check sum as it writes), then read it all back and verify you get the right checksum. Oh and compute read/write times while doing so. If the read back data doesn’t validate, or you can’t write the amount expected, or the read/write rates don’t match expected? faaaaaaake Pretty accurate too. I personally never had an actual fake Sandisk SD card from Amazon. I bought probably 50 of them in the space of 6 months at one point. Other brands were not great. USB flash drives though? Literally all trash. I tried at least 5 different ones before I just gave up. No idea what the market looks like now however.
hashier 2y ago
Ref 2 You mean a simple reformat with fat? Or what’s in your opinion the best test when getting a new SD card?
- megous 2y ago
  Write pseudorandom data to the whole card with a fixed seed. Read back data and compare against the same pseudorandom data with a same fixed seed. Or just make a random data file the size of SD card and write/read back compare, if you don't care about having to store the big file and also testing for potential local disk corruption at the same time.
  - noja 2y ago
    Or use https://github.com/dkrahmer/MediaTester https://github.com/dkrahmer/MediaTester
    - hashier 2y ago
      Looks interesting but unfortunately a windows tool. Happen to know a Linux tool?
      - mohaba 2y ago
        https://fight-flash-fraud.readthedocs.io/en/stable/ https://fight-flash-fraud.readthedocs.io/en/stable/
        megous 2y ago
        I'd rather use something that works with block device directly, rather than something that depends on the filesystem code and may lead to filesystem corruption and potential for kernel instability. Also it seems like a weird design decision to fill flash with files, when in Linux there's trivial access to block device directly. It's also possible to write 64bit address of each 8 byte block to every such block, and avoid pseudorandom generator, and potentially have more insight to what happened when the block ends up mapped to unexpected location.
jdietrich 2y ago
>All microSD cards have a high failure rate. You can buy genuinely reliable microSD cards, if you really need them. Delkin, Innodisk, Swissbit and others make industrial microSD cards with SLC flash, ECC, SMART and power loss protection. Capacities are small and you'll pay a steep premium, but they legitimately have endurance and MTBFs that compete with conventional SSDs.
- crispyambulance 2y ago
  This is true. You can get "industrial" versions of these cards that are intended to be used as BOM items for products. This means you get a stable supply and they won't change the part number out from under you (which happens even with reputable suppliers when you buy as a consumer). When they're about to EOL the part, you get a heads-up multiple months in advance and a "last time buy" opportunity. In my experience, these aren't "better" performance-wise. You just "know" what you're getting, have an opportunity to qualify it, and you won't get surprise changes. Of course, the price is jacked up as a result. Generally speaking, it's usually better to make the customer responsible for the SD card if you have to use one at all.
KMnO4 2y ago
Important thing you should be aware of: not all counterfeit cards fail a format/f3 test. I recently bought a very expensive Sandisk Extreme UHS-II V90 card from Amazon. It passed without any issue when doing a full capacity check, but was still fake because they were using slower (150mb/s vs 300mb/s) flash. The average user[0] would never know, because it was definitely “faster” than other cards and maxed out the UHS-I reader in my MacBook Pro. I returned it and bought from my local camera store (Henry’s) and the performance difference was very obvious. [0]: I guess you could argue that the average user wouldn’t be buying a $200 V90 card, but I still think you could fall victim to this if you didn’t explicitly own a dedicated UHS-II reader.
deleted 2y ago
[deleted]
megous 2y ago
1) I have ~7 cards (all from China and Sandisk, solely because Sandisk has a website where you can verify the card is genuine) that are in daily 24/7 use for 6-8 years with no issues (mounted in rw mode) 2) ... 4) that's true for any storage media If you ever tried running uSD card in SDR104 mode, you'd notice that they tend to heat up way more than in lower speed interface modes. So for longetivity, I guess it's better to run them at HS mode (which is just 50MHz), or at least lower the SDR104 bus frequency from 200MHz to something lower.

matsemann 2y ago

Ref 2: if you buy from Amazon, you never know if you get a genuine card. Even if you shop from an official seller, as inventory is commingled so you might as well get a fake one from another seller with the same SKU. Big problem in action cam related circles, where lots of people have broken recordings due to fake cards.

everybodyknows 2y ago
Are you saying that the counterfeiting of name brand packaging is so skillful that even careful inspection by us the consumers cannot reasonably hope to detect it?
- AlexandrB 2y ago
  Unless you have the real and the fake side by side it can be really hard.
  - dboreham 2y ago
    Even then it's hard because the legit vendors change their packaging frequently.
- cwillu 2y ago
  https://www.bunniestudios.com/blog/on-microsd-problems/ https://www.bunniestudios.com/blog/on-microsd-problems/ “One vendor in particular interested me; it was literally a mom, pop and one young child sitting in a small stall of the mobile phone market, and they were busily slapping dozens of non-Kingston marked cards into Kingston retail packaging. They had no desire to sell to me, but I was persistent; this card interested me in particular because it also had the broken “D” logo but no Kingston marking.”
- Forgeties79 2y ago
  Yes it’s a very big problem until you run speed tests and the like which most people have no clue how to do.
jqpabc123 2y ago
if you buy from Amazon, you never know if you get a genuine card. Yes, but there is a significant difference --- I can always return it to Amazon postage free if the capacity is fake and it won't format properly. Presumably, Amazon extracts the appropriate weight in flesh from the seller. The way retail typically works in the USA, the vendor assumes all the risk --- any problems get unrolled backwards. You can sell a fake product on Amazon --- but it will likely cost you --- not Amazon (who controls the money) nor the end consumer if he is astute. Basically, Amazon acts like an escrow service.
- Palomides 2y ago
  you're still feeding the machine, and assuming you can catch cases where something is merely lower quality rather than completely fake
  - jqpabc123 2y ago
    If there are too many returns, the machine doesn't get fed; it gets punished. Amazon and other retailers have played this game for a very long time and they aren't in it to lose money. In my experience, the thing most commonly faked with memory cards is the capacity --- for example, an 8Gb card altered to appear 64Gb, until it is formatted. If you want extra assurance, buy Amazon branded cards. In this case, Amazon assumes almost all the risk so there is little incentive for fakery.
    - Forgeties79 2y ago
      > If there are too many returns, the machine doesn't get fed; it gets punished. On Amazon? I highly doubt it. The threshold for “too many returns” is probably rarely hit. MicroSD’s are super cheap - people don’t return things that are cheap because they don’t consider it worth their time. Then these companies go and pay people for good reviews and just keep flipping inconsistent/garbage products. If punishment were a real thing that companies had to deal with then this wouldn’t continue to be a problem. It’s been this way for many, many years. Amazon has no equal competitor, there’s nowhere else for folks to go and people rarely look at the specific vendor they’re buying from. As far as they’re concerned it’s all Amazon.
mikae1 2y ago
First rule: never buy flash storage from Amazon.
lazide 2y ago
Personally I found an easy way to tell - write a script which fills the drive fully with random data (computing a check sum as it writes), then read it all back and verify you get the right checksum. Oh and compute read/write times while doing so. If the read back data doesn’t validate, or you can’t write the amount expected, or the read/write rates don’t match expected? faaaaaaake Pretty accurate too. I personally never had an actual fake Sandisk SD card from Amazon. I bought probably 50 of them in the space of 6 months at one point. Other brands were not great. USB flash drives though? Literally all trash. I tried at least 5 different ones before I just gave up. No idea what the market looks like now however.

hashier 2y ago

Ref 2 You mean a simple reformat with fat? Or what’s in your opinion the best test when getting a new SD card?

megous 2y ago
Write pseudorandom data to the whole card with a fixed seed. Read back data and compare against the same pseudorandom data with a same fixed seed. Or just make a random data file the size of SD card and write/read back compare, if you don't care about having to store the big file and also testing for potential local disk corruption at the same time.
- noja 2y ago
  Or use https://github.com/dkrahmer/MediaTester https://github.com/dkrahmer/MediaTester
  - hashier 2y ago
    Looks interesting but unfortunately a windows tool. Happen to know a Linux tool?
    - mohaba 2y ago
      https://fight-flash-fraud.readthedocs.io/en/stable/ https://fight-flash-fraud.readthedocs.io/en/stable/
      - megous 2y ago
        I'd rather use something that works with block device directly, rather than something that depends on the filesystem code and may lead to filesystem corruption and potential for kernel instability. Also it seems like a weird design decision to fill flash with files, when in Linux there's trivial access to block device directly. It's also possible to write 64bit address of each 8 byte block to every such block, and avoid pseudorandom generator, and potentially have more insight to what happened when the block ends up mapped to unexpected location.

jdietrich 2y ago

>All microSD cards have a high failure rate. You can buy genuinely reliable microSD cards, if you really need them. Delkin, Innodisk, Swissbit and others make industrial microSD cards with SLC flash, ECC, SMART and power loss protection. Capacities are small and you'll pay a steep premium, but they legitimately have endurance and MTBFs that compete with conventional SSDs.

crispyambulance 2y ago
This is true. You can get "industrial" versions of these cards that are intended to be used as BOM items for products. This means you get a stable supply and they won't change the part number out from under you (which happens even with reputable suppliers when you buy as a consumer). When they're about to EOL the part, you get a heads-up multiple months in advance and a "last time buy" opportunity. In my experience, these aren't "better" performance-wise. You just "know" what you're getting, have an opportunity to qualify it, and you won't get surprise changes. Of course, the price is jacked up as a result. Generally speaking, it's usually better to make the customer responsible for the SD card if you have to use one at all.

KMnO4 2y ago

Important thing you should be aware of: not all counterfeit cards fail a format/f3 test. I recently bought a very expensive Sandisk Extreme UHS-II V90 card from Amazon. It passed without any issue when doing a full capacity check, but was still fake because they were using slower (150mb/s vs 300mb/s) flash. The average user[0] would never know, because it was definitely “faster” than other cards and maxed out the UHS-I reader in my MacBook Pro. I returned it and bought from my local camera store (Henry’s) and the performance difference was very obvious. [0]: I guess you could argue that the average user wouldn’t be buying a $200 V90 card, but I still think you could fall victim to this if you didn’t explicitly own a dedicated UHS-II reader.

deleted 2y ago

[deleted]

megous 2y ago

1) I have ~7 cards (all from China and Sandisk, solely because Sandisk has a website where you can verify the card is genuine) that are in daily 24/7 use for 6-8 years with no issues (mounted in rw mode) 2) ... 4) that's true for any storage media If you ever tried running uSD card in SDR104 mode, you'd notice that they tend to heat up way more than in lower speed interface modes. So for longetivity, I guess it's better to run them at HS mode (which is just 50MHz), or at least lower the SDR104 bus frequency from 200MHz to something lower.