64GB is already a house number. Reading the data goes vorran somewhat slow compared with other sticks. However, the writing is my opinion, very tedious. I use the stick on Win 7 with two computers. One computer will recognize the stick is not always. The Reason? No Idea. The processing of the stick is OK. It is in the product description does not mention from which operating systems the thing is supported. XP goes eg. not. That's for a Nichtcomputernerd already a problem.