Catching up with TMO after some absence and coming back to this thread. It seems that my el-cheapo 16 GB card is doing about as well as otber people's super-duper 64 or 128 GB. In other words, it is not my card that is the bottleneck. What else might it possibly be, I wonder

It might be interesting to compare the results for the same card between a Jolla and a desktop.