(05-02-2016, 01:02 AM)xrez Wrote: they should really start rating random i/o speeds imho
This won't happen anytime soon so it's the responsibility of SBC vendors to stop recommending crap like 'choose any class 10 rated SD card' and to inform their users what's really important.
I don't know much about Android and lack the skills to debug Android stuff. But it was absolutely easy to reproduce this behaviour. I tested RemixOS with a 32GB Samsung EVO and with an Intenso 4GB crap card. Difference like day and night since the Intenso showed 30 times lower random I/O performance. With this card RemixOS was not useable and the whole user experience was just 'stuttering all the time'.
And a few months ago when I tested some Armbian Desktop builds for H3 boards (share the same SDIO implementation with Pine64) I was able to debug the dependency on fast random writes. If you open up something like Firefox for example then this app starts constantly writing to the card, uses fsync calls to ensure changes are written to card immediately and this alone blocks nearly all I/O when used with an 'average SD card' (see the Kingston and PNY numbers from this thread and compare with the even cheaper Samsung EVOs that outperform the aforementioned many times). It's explained here: https://wiki.mozilla.org/Performance/Avo...O_Patterns
And if you read this and then test the SD card in question with 32KB record size just to realize that many/most cards show really bad write performance with 16K and 32K then everything is pretty obvious: You have been fooled by irrelevant speed class ratings and your whole 'user experience' sucks simply since the OS is constantly stuck in I/O processes since random writes are way too slow.