I take this memory card in my Sony alpha SLT-A57. It seems as if they where "perfect" works. At least I had no trouble with it. When I put the card into the card reader of my PC, I am pleasantly surprised at how fast the read access to this card. 300 ... 400 MB of data are "Ruck-Zuck" copied. These details are all "subjective" because I have neither time nor inclination for comprehensive performance measurement and benchmarking.