Need to change the memory card from my HTC Sensation (not room and board not fast enough - Class 4). I ended up choosing the card that is delivered quickly (mine is black and not white) and even faster inserted into the phone said. The change is obvious in videos in Full HD (1920 * 1080), more than saccade, really smooth video. On the packaging there wrote "Read Max 24 MB / S - Max Write 21 MB / s". Here are the results of a test performed with ChristalDiskMark: Seq: 18.04 MB / s read - 14.26 MB / s éciture. 512k: 12.89 MB / s read - 1,664 MB / s write 4k: 2,159 MB / s read - 0.198 MB / s write. 4K QD32: 2,428 MB / s read. In the end, even if there is a discrepancy with official data (as usual), I am for now happy with this purchase.