SD card speed

[MadMac]

I have 2 32GB cards, one does 40/20MB/s the other 80/10MB/s, +-, as measured. Both class 10. I understand there are some limits on the SD bus, thus you can not use max speed a card may eventually provide.

 

So my question, which one would be preferred ti be be used? 40/20 or 80/10. Thanks.

[tkaiser]

12 minutes ago, MadMac said:

So my question, which one would be preferred ti be be used? 40/20 or 80/10.

 

If you want to focus on sequential performance (which is most probably NOT what you should do), then keep in mind that on H3 boards the sequential maximum is ~23 MB/s. So you're talking about '23/20 or 23/10' anyway and it's pretty easy what to prefer though the numbers above look somewhat bogus anyway.

 

Some background info (and why most probably looking at random IO is way better which needs a test on the device itself): https://forum.armbian.com/topic/954-sd-card-performance/

 

[MadMac]

Thanks, appreciated, I measured the 2 cards, and writing speed appears to be the difference.

 

What is it going to be used for? Crypto mining, particularly DeepOnion. It may not make much difference with the writing speed for this.

 

May also run some other staking cryptos in parallel like IFLT and EMB, but one by one.

[hojnikb]

Avoid sequential performance, because thats meaningless in the context of single board computers. What you should be focusing is random performance (4k-1 and 4k-32) which normally sux with cheap cards (think 0,01MB/s).

Exception to this are samsung evo/evo+ cards, which have very good random 4k performance for SD card. At least that used to be the case, please someone correct me if i'm wrong.