My Sandisk Ultra micro sd was taking a long time to transfer files. I’ve looked into the problem and now done the following, performed a full format in exfat with SDFormatter, then peformed a full write/read test in H2testw.
The write speed as reported by H2testw is 5.54 Mbyte/s, well below class 10 minimum of 10 Mbyte/s.
Question is can I apply for replacement and begin RMA process? I’m in the UK and bought from Amazon