>what speed do applications set for sd cards?
This I know a bit about
Application does not set speed, it is an intereletion between hardware and drivers
And you NEVER reach the theoretical maximum
Normal speed, all cards 50mhz, nibbles, in real life ~23MB/s, not 25
If the card is capable, traces balanced, 1.8V capable, clock capable,, you may see
I think called sdr204, anyway 100+MB/s,, and you won't see that,
maybe close for reading large blocks (and there are other, lower frequencies, slower)
Writing is always worse, sometimes a lot worse
Run some iozone tests, you will see,, 4k and 16k particularly bad
And this last point is how to tell how bad the card is, poor to terrible
maybe someday we will see 3d-xpoint in cards, I'm not holding my breath
A quite good card, writing an image, dd bs=1M status=progress will be 40MB/s
This I know a bit about
Application does not set speed, it is an intereletion between hardware and drivers
And you NEVER reach the theoretical maximum
Normal speed, all cards 50mhz, nibbles, in real life ~23MB/s, not 25
If the card is capable, traces balanced, 1.8V capable, clock capable,, you may see
I think called sdr204, anyway 100+MB/s,, and you won't see that,
maybe close for reading large blocks (and there are other, lower frequencies, slower)
Writing is always worse, sometimes a lot worse
Run some iozone tests, you will see,, 4k and 16k particularly bad
And this last point is how to tell how bad the card is, poor to terrible
maybe someday we will see 3d-xpoint in cards, I'm not holding my breath
A quite good card, writing an image, dd bs=1M status=progress will be 40MB/s
