5 ms·

>I found a USB 3.0 SSD was ten times faster than the fastest microSD card I tested I looked it up because i know enough about hardware that this shouldn't be t

>I found a USB 3.0 SSD was ten times faster than the fastest microSD card I tested I looked it up because i know enough about hardware that this shouldn't be the case (even with a cheap SD Card). Seems it's a limitation of the Pi's SD Card slot. https://www.jeffgeerling.com/blog/2018/raspberry-pi-microsd-card-performance-comparison-2018 https://www.jeffgeerling.com/blog/2018/raspberry-pi-microsd-...

UnlockedSecrets 6y ago
Note this is only valid for raspberry pi's made before the 4, The 4 includes a much faster SD card slot.
- mlyle 6y ago
  Note that the testing was done on a Pi 4...
  - UnlockedSecrets 6y ago
    > tested on a Raspberry Pi model 3 B+: No it wasn't.
    - geerlingguy 6y ago
      This one, however, was: https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance-comparison-2019 https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-... Even on my Mac (tested with 6 different readers, including one purporting A2 compatibility) the best microSD cards are abysmal for random access. But they do get closer to 90-120 MB/sec for reads, at least. To get advertised speeds on most of the cards, I am guessing you need to work for the SD association's marketing department :D https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-follow-sd-association-fools-me-twice https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-...
      - kohtatsu 6y ago
        Wow great review, thank you.
      - mlyle 6y ago
        > To get advertised speeds on most of the cards, I am guessing you need to work for the SD association's marketing department Note that there's all kinds of special, video camera-oriented things in the SD standard, where you can preallocate/pre-erase a big chunk to sequentially write, stream data in and do big commits. That's where you actually hit the rated speeds, because the flash controller is able to benefit from all the hinting. Using SD with general purpose filesystem drivers, etc, is really just a very common edge case.
    - mlyle 6y ago
      I believed you were writing about analysis linked in parent article (you know, the article we're all discussing), where he compares USB3.0 throughput to SD on the Raspberry Pi 4, and finds speed differences of 3-16x+: https://www.jeffgeerling.com/blog/2020/im-booting-my-raspberry-pi-4-usb-ssd https://www.jeffgeerling.com/blog/2020/im-booting-my-raspber... Now I see that someone linked another article inbetween, which you beat up for being on 3B+, but the conclusions remain largely the same when tested on the 4. And note that these tests were without UASP on the USB drive, so USB was handicapped.
aspenmayer 6y ago
This is more up-to-date, and includes more models of Pi’s and SD cards. It was linked in your post, but the post is now out-of-date relative to my link below. https://pidramble.com/wiki/benchmarks/microsd-cards https://pidramble.com/wiki/benchmarks/microsd-cards
- geerlingguy 6y ago
  If you want to bookmark a page, that's the one that I update every year or two (usually after a new Pi model is released). The blog posts fade a little in relevance over time since I don't keep them updated.
  - aspenmayer 6y ago
    Thanks for all the work you’ve put in to this. I hope we see a Pi with NVMe soon.
megous 6y ago
Not really, even the fast microSD cards have ~1000 IOPS. Regular A1 cards have 500 random address write IOPS. Most USB attached SSDs will top that many times over. It's not really hard to top 2-4 MiB/s write speeds by an order of magnitude.

UnlockedSecrets 6y ago

Note this is only valid for raspberry pi's made before the 4, The 4 includes a much faster SD card slot.

mlyle 6y ago
Note that the testing was done on a Pi 4...
- UnlockedSecrets 6y ago
  > tested on a Raspberry Pi model 3 B+: No it wasn't.
  - geerlingguy 6y ago
    This one, however, was: https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance-comparison-2019 https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-... Even on my Mac (tested with 6 different readers, including one purporting A2 compatibility) the best microSD cards are abysmal for random access. But they do get closer to 90-120 MB/sec for reads, at least. To get advertised speeds on most of the cards, I am guessing you need to work for the SD association's marketing department :D https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-follow-sd-association-fools-me-twice https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-...
    - kohtatsu 6y ago
      Wow great review, thank you.
    - mlyle 6y ago
      > To get advertised speeds on most of the cards, I am guessing you need to work for the SD association's marketing department Note that there's all kinds of special, video camera-oriented things in the SD standard, where you can preallocate/pre-erase a big chunk to sequentially write, stream data in and do big commits. That's where you actually hit the rated speeds, because the flash controller is able to benefit from all the hinting. Using SD with general purpose filesystem drivers, etc, is really just a very common edge case.
  - mlyle 6y ago
    I believed you were writing about analysis linked in parent article (you know, the article we're all discussing), where he compares USB3.0 throughput to SD on the Raspberry Pi 4, and finds speed differences of 3-16x+: https://www.jeffgeerling.com/blog/2020/im-booting-my-raspberry-pi-4-usb-ssd https://www.jeffgeerling.com/blog/2020/im-booting-my-raspber... Now I see that someone linked another article inbetween, which you beat up for being on 3B+, but the conclusions remain largely the same when tested on the 4. And note that these tests were without UASP on the USB drive, so USB was handicapped.

aspenmayer 6y ago

This is more up-to-date, and includes more models of Pi’s and SD cards. It was linked in your post, but the post is now out-of-date relative to my link below. https://pidramble.com/wiki/benchmarks/microsd-cards https://pidramble.com/wiki/benchmarks/microsd-cards

geerlingguy 6y ago
If you want to bookmark a page, that's the one that I update every year or two (usually after a new Pi model is released). The blog posts fade a little in relevance over time since I don't keep them updated.
- aspenmayer 6y ago
  Thanks for all the work you’ve put in to this. I hope we see a Pi with NVMe soon.

megous 6y ago

Not really, even the fast microSD cards have ~1000 IOPS. Regular A1 cards have 500 random address write IOPS. Most USB attached SSDs will top that many times over. It's not really hard to top 2-4 MiB/s write speeds by an order of magnitude.