I purchased the card in the Sandisk packaging, so I am pretty sure it is genuine. I tested it with various programs on the web that apparently can detect whether they are fakes or not. This one turned out to be a real Sandisk card. The card came formatted with FAT32.I read on the web about these micro SDs, and apparently they are not as fast as the full SD card version. I borrowed my brothers Sandisk 32gb full SD card to make comparison tests. Here are my official/unofficial test results using DiskBench V2.6.2.0 and H2testw 1.4 test. I will give the results as an "overall" result, because after testing these cards over and over with speed writes and reads, the results get mixed and varied to a big degree... much larger than I expected, but the numerous tests showed me a "general" trend. The trend is that the full SD cards do write faster than the MicroSD card. But, also remember that the microSD had to be put into an adapter to do the test on my PC while the fullSD card was put into the computer reader directly.These are just my averages, but:Small file writes:Both SD cards wrote at close to 10mb/sec. The microSD was less consistent in the tests and sometimes dropped to 8mb/sec.Small file reads:Both SD cards read at close to 20 mb/sec at their fastest.Large file copies to card:MicroSD wrote at 3.5mb/sec while the fullSD wrote at about 4mb/secLarge file reads copies from card:MicroSD was 10mb/sec while the fullSD read at about 14mb/sec.My conclusion:My tests were by no means official for this card and showed much variance dependent on file size of the reads and writes, but the fullSD card was faster in many cases, but equal to microSD in most cases. The small file writes and reads showed that they are similar enough. But, my only concern is with large file writes.... is 3.5 mb/sec good enough for rapid photography on a high pixel camera? I don't know. I have had no problem using these cards with H264 movie capture for hours. I am surprised that 3.5 mb/sec is enough.Also, never during the huge file copies to the card did I get any noticeable heating of the card itself, by touch even for an hour. I've noticed that it has been a complaint from many people on the web, some stating that they felt they might burn themselves. I copied files that took more than an hour with no noticeable temperature change, other than, perhaps a couple of degrees. Of course, this was on a PC and not installed in a camera.The card performs well for video work, and appears to meet many other tests performed by other people. I never saw a read close to 30 mb/sec... they were very consistent at 20 mb/sec at the highest performance.I would get the card again, if the price were right.