This is the speed test result for the previous 64gb card (about 5 years old). Both cards are sandisk Ultra, both rated 10

It's possible that the new card may be faulty as I was getting slight gliches when music played and the album art had to load in every time I opened the app. On the previous card it only did this when new music was added.
I think i'll be returning it as faulty but i'm surprised that the difference in advertised and actual speeds is so huge.
edit. Actually the above is the 32gb result. (I've been swapping cards around)
This is the result for the previous 64gb micro sd in my phone. Read: 19.30, Write: 9.68

The write speed on the recently bought sd seems to be an indication of faultiness as the other two cards seem to have consistent scores.