The best card to use with the xxxxD line of cameras seems to be the SDHC cards, 32GB or smaller. Many users seem to experience memory card failure messages with the SDXC cards, 64GB or larger. Success rate with the larger capacity cards seems to be pretty much hit or msss. One things seems to be certain. The larger and larger the card capacity, the more likely you are to experience memory card errors.
As far as R/W speed goes, the top R/W speeds of your camera are defined and limited by your camera hardware, not the memory card. Using a higher performance card will not speed up your camera. Just as using a higher performance fuel in your car will not increase fuel efficiency, using a higher performance card will not increase the R/W speed of your camera.
One last thing before I go. SD memory cards should [NOT] be regarded as temporary storage. They are not robust enough to store data for long periods of time. Always copy your image files out of the camera without much delay. And always remember to use the camera to perform a low level format on a memory card prior to first use.
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"The right mouse button is your friend."
