You may want to have a look at this thread:
http://forums.windowscentral.com/ask...t-sd-card.html
Unfortunately, I don't have access to the technical specifications at that level. In the thread I posted above, using the Hardware tests app should enable the user to determine the speed of the SD Card.
By the way, I just did some reading, have a look at this page:
Difference between Speed Class, UHS Speed Class, and Speed Ratings (performance) for SD/SDHC/SDXC cards
as well as this page:
http://www.lexar.com/files/product/d...HS_Final_1.pdf
Class 10 is rated only at 10MB/s, while cards that go up to 90MB/s have a different rating "Professional 600x UHS-I". You may want to check if the SD Cards you're choosing are legitimate.
