Shopping for a SD card if speed is important to you is difficult. All SD cards look the same no matter how much capacity they have or how fast they are leaving the shopper to trust the logos and packaging to make a purchase.
The SD Association has announced new logos to help identify the faster memory cards on the marker. The new logos will go on cards meeting UHS-I specifications. The logo will only be used on SDXC and SDHC cards and promises data transfer of up to 104MB/s.
That speed is fast enough to record live HD video in real-time. Apparently, the spec promises at least 25MB/s of data transfer.