Shopping around for a new MicroSD card for your BlackBerry? Totally confused about what the difference is between a Class 4 and a Class 6 device? Wondering what 133x or 66x or 32x means?
Turns out that it is quite simple. The class defines the minimum write speed for a completely empty SD card. That means if you were writing to a new SD card that has never had any data on it how fast would it write.
- Class 2 = 2 megabytes/second
- Class 4 = 4 megabytes/second
- Class 6 = 6 megabytes/second
So in short Class 6 is what you should be buying for fast write speeds. On top of this there is also the speed rating of the card itself. This is based on how fast the microSD card can READ the data off the card. You will see this usually described as 32x, or 66x, or 133x, or something with an x and the end.
These measurements are based on the original CD-ROM drives which could write 150kb/second. So 32x means 32 multiplied by 150kb/second or 4.8MB/second. This nice little table from Wikipedia gives you a basic idea of what each one stands for in terms of speed:
Let me know if you have any more questions!