FWIW, I purchased 2 more cards from Costco, so now only 1/6 cards were defective. Still worth benchmarking each before use, however. At 10:14 AM 2/15/2015, James Propp wrote:
Henry,
If you'd bought just one card, and it was defective, would you be "amazed to find that perhaps 100% of these devices did not meet their speed requirement"?
:-)
(Kidding aside, I do get where Henry's coming from. And, in the absence of priors, maybe 25% is the best estimate.)
Jim Propp
On Sun, Feb 15, 2015 at 10:19 AM, Henry Baker <hbaker1@pipeline.com> wrote:
I purchased 4 32GB uSD cards from Costco yesterday, and found to my amazement that one of the devices was faulty: while the maximum write rate was >20 MB/s, its minimum write rate was 1.2 MB/s, with an average write rate of 5.1 MB/s.
While I suspect that this defective device will function correctly as a memory, I was amazed to find that perhaps 25% of these devices did not meet their speed requirement.
BTW, if you run Linux, there is a "benchmarking" function for the disk formatting program which is quite useful.
Now I'm going to have to test all of my SD cards in advance prior to using them.