@giantsfan3: thanks 
ok for the post, but can´t do it today. Maybe with a title like '[Info] Example measurement for high speed ADC & SD Card writing' and maybe asking interested folks what the would be interested in to be measured further.
I looked at playground -> storagy....am unsure if my post already qualifies for the playground olymp 
For example I didn´t add the info, which hardware I used, which SD card etc. So it´s no qualified measurement in the sense.
I´m wondering more if a kind of 'getting started with Ardiuno & SD' would help people more (After reading some of the topics in this forum....). Something along these lines
- Working example of setting up the hardware + simple sketch to basically test if it works in principle (people could also be asked to try this before posting questions ) ; could be complemented over time with 'proven SD cards'
- Basic steps to analyze issues (memory consumption, frequency/data volume of updates to/read from SD)
- Decision tree along some questions ( a) volume of data to be written (b) which frequency to you want to log with...). There will also be some ends in the decision tree that end in 'Do not use an arduino, better get a digital scope...')
Opinions?