This is a class 4 SD card. It has a minimum write speed of 4MB/s. The 60X means that it has a maximum possible write speed of 9MB/s. That doesn't mean it will write at 9MB/s. It means you can't expect it to write at 10MB/s. So it can be anywhere between 4-9Mb/s. It is very misleading to state a transfer speed of 9MB/s

I always wonder, what make a high class SD card read and write faster than the lower class one. Is it the internal configuration? or they use better conductor to increase the votage through put of the card? Why the F*&$ can they just make every SD card class 10 and stop this S

#2 - short answer is cost, long answer requires an electrical engineering degree. Your question is like asking why don't they make all CPUs run at 5 Ghz...

Its the cost of making the memory. There's SLC and MLC. SLC's faster but it costs more money to make. And MLC which packs more into the same space, costs less but is much slower.

MLC's been improving over the years as you are seeing class 4 stuff getting cheaper and more available. Class 10 only came out because SLC's improved in speed and USB 3.0 will be able to use it.

If I'm not mistaken, I believe # 4 just called you a DA #2!!!

This is a Class 4, you can see the number 4 circled by the letter C. Not a bad price for 16GB.

Class 4? beh. Elementary school.