4 ms·

My experience is that normal SanDisc SD cards are the best. Other brands are unusable because of latency of write/read time! You need to power them when you buy

by bullen 6y ago

My experience is that normal SanDisc SD cards are the best. Other brands are unusable because of latency of write/read time! You need to power them when you buy them though, otherwise they actually break sometimes, and I don't mean data loss; I mean break! This means you should try to buy them as fresh as possible and since sellers don't show production dates that means you have to wait for new models to come out and buy them then. To me the most important metric is not speed of bandwidth but speed of time and stability! Does anyone have measures of how the SSD compares to SD card in terms of write/read latency? I have only had problems with USB <-> SATA, the stability of USB3 drivers is a joke!

dws 6y ago
I've yet to have an issue with a Samsung Evo (or Evo+) card.
geerlingguy 6y ago
I've been doing comprehensive tests for five years now, and found that SanDisk and Samsung cards are orders of magnitude better than all other brands. Here's my 2019 update: https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance-comparison-2019 https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-... I've had three Pis running more or less continuously off a microSD for a few years, and none of those cards (same as original) have gotten corrupted. These aren't running zillions of writers per day or anything, but most people's problems stem more from bad power supplies or cheap cards than the Pi's use of microSD itself.
- bullen 6y ago
  You should probably run iostat in your tests too, to have high bandwidth is completely useless if it has high latency. Just like a high framrate game is unplayable if the frames are instead delayed so the motion to photon delay is many frames. Companies are now cheating in every way they can to extend and pretend, and now as the peak density on the flash media reveals that they break with time it's going to get messy!

by bullen 6y ago

dws 6y ago

I've yet to have an issue with a Samsung Evo (or Evo+) card.

geerlingguy 6y ago

I've been doing comprehensive tests for five years now, and found that SanDisk and Samsung cards are orders of magnitude better than all other brands. Here's my 2019 update: https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance-comparison-2019 https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-... I've had three Pis running more or less continuously off a microSD for a few years, and none of those cards (same as original) have gotten corrupted. These aren't running zillions of writers per day or anything, but most people's problems stem more from bad power supplies or cheap cards than the Pi's use of microSD itself.

bullen 6y ago
You should probably run iostat in your tests too, to have high bandwidth is completely useless if it has high latency. Just like a high framrate game is unplayable if the frames are instead delayed so the motion to photon delay is many frames. Companies are now cheating in every way they can to extend and pretend, and now as the peak density on the flash media reveals that they break with time it's going to get messy!