Great speed in my smartphone Samsung S8+ for hi-res photos and 4K videos.
I tested the read/write speed using the App "A1 SD Bench" by Tuxera and it didn't show the advertised speed but that could be for many reasons on the phone side...
Using the Quick test I have reached a reading speed of 66.2MB/s and a writing speed of 63.0MB/s
Using the Default test I have reached a reading speed of 67.5MB/s and a writing speed of 69.2MB/s
Not that bad comparing other online results
da_chevalierThe reason you aren't getting advertised speeds is because the S8 doesn't support UHS-II speeds. In fact, I don't think any Android smartphone supports UHS-II.
Not that bad comparing other online results