My brother bought a card of another brand in 32GB Class 10, making a copy of the same image (for my small computer rasbperry ft), on my side I had an almost constant copy of 15MB / s write , meanwhile it was between 8 and 14MB / s write. I also bought the 16GB model of the same manufacturer in Class 10. It turns out that the card is slightly slower (copy of the image to 12MB / s average). For 10 class (meaning at least 10MB / s write), I am obviously very satisfied.