[math-fun] Defective Sandisk uSD cards

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.