So with this card, you will have currently no slowness of writing a file, the last go-pro (the HERO4 BLACK) calls 50M / S write, so you have almost double.
to remember to use these speed on pc, went through a USB drive 3 USB 2 or else you will be limited to 30m / s.
for a smartphone (later in 2014 because none can write as fast) thought his writing looked on maximum speed micro SD, there is no point to take this card if your phone can not write faster than 50m / s, in this SANDISK EXTREME take a case, prices will have time to get off phone before you change it, no need to spend more not used the full potential of the card before some years.
if that comment helped you thank you note to the