Why is my SD Card not accurate in Read and Write

[AC Question]

Good Day

Am not sure if this is the right category or thread. But I'm wondering on what I bought

I bought a Samsung 64GB Pro Micro SDXC UHS-1 that should be around 90MB/s of Read and 80MB/s.

I tried benchmarking it using the A1 SD Bench and the result is:
Read: 40.54 MB/s
Write: 37.73 MB/s




So as you can see it's not accurate. Also this is formatted to exFAT.