Memory card write speeds.

I just bought 6 new memory cards. All 64Gb. All SDXC. All microSD.

write speed cost in pounds class / spec make / model
8.8 MB/s 11.50p UHS-1 / class 10 Kingston.
17.0 MB/s 14.98p UHS-1 / class 10 SanDisk Ultra
20.0 MB/s 22.44p UHS-3 / class 10 SanDisk Extreme

So: the difference between kingston and SanDisk Ultra was worth paying for, (twice speed for 4 pounds more). But the Ultra -> Extreme wasn’t worth it.

These are write speeds (what solo does). I didn’t measure read speeds.

experiment setup: lsusb -t (shows speed of connection on USB devices).

used: dd if=somehting.iso of=/dev/sd? bs=4M ; sync

bs=4M speeds things up. the bigger the better. 40M is no better, though.

bs=512 drops performance to 3.9MB/s absent drops performance to 3.9MB/s (probably defaults to destn blk size)