Test microSD Card in Raspberry Pi
Open a terminal window and login
Run these commands to see if a microSD Card plugged into a Raspberry Pi is running at the advertised speed:
$ sudo apt update
$ sudo apt install agnostics
$ sh /usr/share/agnostics/sdtest.sh
Run 1
prepare-file;0;0;14463;28
seq-write;0;0;16197;31
rand-4k-write;0;0;3527;881
rand-4k-read;6915;1728;0;0
Sequential write speed 16197 KB/sec (target 10000) - PASS
Random write speed 881 IOPS (target 500) - PASS
Random read speed 1728 IOPS (target 1500) - PASS