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Comment by nicoburns | Hacker News Reader

It really is incredible how much storage you can fit in such a tiny volume. However, I think the read/write speeds are now the bottleneck on these devices. They seem to all cap out at around 100MB/s (maybe a little more if you get a premium card), which isn't very fast when your device have 1TB of storage.

I'm looking forward to SD Express https://www.extremetech.com/mobile/286390-sd-association-ann... which aims to solve this issue.

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That depends on your use-case.

The typical use for a microSD card is to store media (photos, audio, short video clips), and if you add it gradually and consume it from a managed media library, you'll have smooth sailing until you one day decide to export it or back it up and find that it takes 2.5 hours to transfer everything, assuming you don't get thermally throttled!

Even though it takes even longer, I've used rsync with bandwidth limiting to get around thermal issues during large reads.

How do you know that rsync with throttling options is faster than the thermal throttling (designed by the manufacturer)?

I don't, but it seemed to work. YMMV.

What are people even doing that they need more than 100MB/s? I can't see myself ever needing more than that for personal use. Even if you need to read or write the whole thing (which I've essentially never had to do for any storage device), it'd take less than 3 hours to do, which isn't very long

The problem is the speed of non-sequential writes and reads. Writes can fall down to Kb/s in some cases, due to the way flash storage works and onboard controllers, that are optimised for sequential loads. So can't use them as a cheap HDD upgrade options.

Agreed. I have tried to supplement a primary drive that is too small and I/O is definitely the bottleneck. So much so that you can't really watch HD video straight from an SD card because it will drop frames or cause other issues due to slow throughput.

So now SD cards get DMA. Fun!

And easily lost.

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