i was reading some reviews about this and honestly i really don't notice the speed. but the storage of it is epic. 64gb card +32gb phone = ... a lot of information.... and i save and store alot of things. For me its a great card to hold stuff and a speed i really don't noticed, However i want to add that this card is not slow i just don't notice the difference using a 32gb class4 vs 64gb class10 on a e890(optimums g PRO)