On Wednesday 07 March 2012, Santiago Castillo Oli wrote:
Hi flashbench-results.
I'm trying to get the most from a Samsung 32Gb SDHC Class10 card.
I've run a flashbench (compiled for x86) on a Asus Eee PC 901.
I'm posting the results as an attached file to this message.
I guess the page size is 16Kb, but not sure about erase block. What do you think?
Strangely the 4 Mb boundary is faster than bigger boundaries.
Hi Santiago,
Sorry for the late reply on this.
I think I've seen two of these cards and they seem to be very interesting in their behavior. The solution to the erase block size question was 6 MB in both cases. You could run flashbench -a --blocksize=3072 to test multiples of 3 here.
If you have a laptop with integrated mmc controller (device shows up as mmcblk0, not sdX), can you post the results of "head /sys/mmcblk0/device/*"? Also, is this a microSDHC or full size SDHC card? I've only tested the micro variation. Also, is it the "plus" series (MB-SPBGA) or the "essential" (MB-SSBGA) version?
I have tested two "essential" microSDHC 32GB (MB-MSBGA) and one "plus" SDHC 8GB (MB-SP8GA). The microSDHC interestingly could support up to 30 (!) erase blocks concurrently being written to, which is better than any other SDHC card I've encountered. I had to make some modifications to flashbench to actually measure that.
The 8 GB "plus" card was also pretty good at 7 erase blocks of 4MB.
Arnd