I don’t know if this info is still of interest but I just got off a call to Sandisk and ultimately to their “technical support for professional memory cards”. My question to them was what is the difference between their item numbers SDSDX3-032G-A31,
SDSDRX3-032G-A21, and SDSDX-032G-X46D. All of these are shown on their website as 32 gb SDHC class 10 cards with a 30 mb/s’ transfer speed. The final answer from their “experts” is there is no difference except for the packaging. They are the same card. SDSRDX3, SDSDX3 and SDSDX all specify the Sandisk Extreme SDHC card: the 032G, of course, specifies the capacity in gigabytes; the A31, A21 and X46D identify the different manufacturing sites where the cards were made.
My next question to them was whether the listed 30 mb/s’ read/write “Max” speed was theoretical or actual as I require a card for a video camera with a 24 mb/s’ tranfer rate to a memory card. The response was that the card will maintain whatever speed the host is sending to it up to a maximum of 30 mb/s’.
I hope this helps someone in addition to me select the right Sandisk SDHC card for their requirements. I can’t believe how confusing this process has been!
