SANDISK EXTREME PRO MICROSDXC UHS-I U3 512 GO 200/140MB/S: VERY FAST!
very fast microSD. Tested with a Kingston microSD/SD adaptor and Kingston Mobilelite Plus USB 3.2 UHS-II "SD" Card Reader for transferring a file of just over 6GB: I obtained a write speed of between 128 and 132 MB/s (very stable write speed), and a read speed of between 185 and 245 MB/s (faster than expected for reading at times!).
For comparison, under the same conditions with a Kingston Canvas Go! Plus 512 GB 170MB/s microSD card, I got a write speed of between 86 and 99 MB/s and a read speed of between 160 and 168 MB/s (but with a big drop in the middle of copying files: speed not stable).
WARNING: the 'quality' of the card reader is important: I had a write speed of around 35MB/s on another memory card reader (Goobay USB 3.0 USB-C without using a microSD/SD adapter) and around 85MB/s on a Lexar 'microSD' UHS-II USB 3.0 card reader.
