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Since they can make 1 TB MicroSD cards, why aren't there larger SD cards?

I checked the size of the NAND Flash packages inside a MicroSD card and it’s two packages, if all it takes is two NAND Flash packages for MicroSD, why can’t we fit more of those tiny NAND Flash packages into a normal size SD card?

Currently a 1 TB MicroSD card uses 2x 512 MB NAND Flash packages.
I estimated a SDcard uses 9x 512 MB NAND Flash packages.

That would come out to ~4.5 TB SD card.

There are certain industries who would want a SD card that big.

And MicroSD cards are WAY too tiny & fidly, they are TOO easy to lose.

I miss MiniSD cards and I estimated that they can fit 6x of the MicroSD size NAND Flash packages, they could potentially bring that back as a form of easy to use, yet small Memory card for normal folks.

It’s simple: anything larger then 1TB takes forever to fill as the communication protocol for removable flash storage isn’t suitable for high density data streams. At best, a card will transfer 10MB per second. Now, 1TB is equal to 1 million MB. So transferring 1TB will take 100,000 seconds. You do the math how many weeks that is :roll_eyes:

I’m sure once SDUC cards start to become a thing we’ll see 2 TB+ SD and microSD cards.

SDUC was announced June 2018, so I don’t doubt that we’re still in the innovator phase of the product adoption curve.

IDK what kind of cards you’re using but the ones im getting are writing near 30MB/s and thats the shitty ones. I have some that rival a mechanical HDD for write speeds.


I have some 2013 era cards doing close 100MB/s reads/writes (sandisk extreme pro, but they’re only 64G)

But yes, all SD stuff has been sloow to pick up on speed or reduce access times.

maybe it was a typo and he meant 100MB/s

Okay than, but I can tell you it is not even in the days, just slightly over 1.

100,000 seconds /60 for minutes
1,666.66667 minutes /60 for hours
27.77778 hours /24 for days
1.157 days

Yeah its a while but you would also not be dumping an entire 1TB right then and there it would be piece by piece over time, and as pointed out the transfer speeds are much higher than 10MB/s

I remember this story from a few years ago. As far as I know these never really took off. But the promise of faster speeds in a microSD sized flash disk sounded great. I think because it was a proprietary format that it never caught on. I would far prefer a faster standard over increasing capacity by too much.

I can’t think of one to be honest.

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No, I was right:

Be aware of the difference between Mbit and Mbyte (MB). theoretically it’s a factor 8, in practice often 10 (overhead et all) and deliberate misrepresentation by manufacturers by stating 100Mb instead of 10MB. Capitals matter when prefixing units of measurements!

As it happens I wasn’t aware of the new “video speed class” as i haven’t had to buy a new SD-card (whatever size) for a fair while.

Are you sure thats the link you wanna go with? because it says otherwise directly on it.

Speed Class*, UHS Speed Class** and Video Speed Class*** symbols with a number indicate minimum writing speed.

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[quote=“Zibob, post:7, topic:159827”]
Yeah its a while but you would also not be dumping an entire 1TB right then and there it would be piece by piece over time, and as pointed out the transfer speeds are much higher than 10MB/s
[/quote]Fair enough, but when your SD card is dying, you really want the data off ASAP. So even with those higher speeds it still takes a fair while doing so, in which time the card may die completely and you’ve lost any remaining data. Linus made a video about this subject (be it for large capacity HDDs) a while ago on one of the LMG channels, if you haven’t seen it yet you should.

Yes, I’m positive. As you correctly quoted, it’s a minimum speed, the manufacturer does NOT guarantee any faster speeds, so anything faster is a bonus for you as user. It also means you can’t rely on those higher speeds to be present on any newly purchased card. They usually are, but if you’ve got a “monday-morning” product that just meets those minimum speeds, you’re out of luck.

This is a fair point. Also just because a card may be capable of R/W at those speeds doesnt mean you’re going to get them in whatever card reader you’re using.

The formfactor overall just doesnt make a whole lot of sense for fast and dense storage IMO.

I concur with this, but your statement originally was


should be

at worst

Theres plenty of people on scamazon posting crystaldiskmark screenshots of their sequential R/W. Now your other arguments about them being too unreliable for higher densities is probably true. I think also people look at them in a different light from other storage mediums. They expect these things to be cheap and so they go out of their way to buy the cheap one. The nicer ones dont sell well to the general public.


I have 32GB Sandisk Extreme Pro cards from half a decade ago that read over 90MB/s and write over 40MB/s. Newer ones can write 90MB/s.

And no, not Mbits. MEGABYTES.

Sandisk had that class of cards for as long as I can remember and they straight up tell you the speeds. Not guesswork.

You’re statements on SD card speeds are incorrect.

Photographers would most likely prefer 128GB but RAID1 in the card.

Standard cards are 12.5MB/s, UHS-III (mostly used for filming) are 625MB/s and up.

And recently this here:


ah, so they are finally updating the interface to push the tech.

UHS-I and UHS-II have been arround for a bit, have not seen UHS-III in a device yet.

I have yet to see anything like this anywhere, but I also dont really use anything requiring fast SD cards.


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