SD memory cards are available in capacities up to 128 GB and im various speed grades. High performance SD memory products are usually based on the UHS-I interface and currently deliver up to 633X speeds. This is based on single-speed CD ROM throughput of 150 kB/s and means a maximum throughput of 95 MB/s to or from the SD memory card. We use a Core i5-2400 on a Gigabyte Z77 G1.Sniper M3 and SanDisk's USB 3.0 card reader Image Mate All-In-One to check these performance statements. SD memory cards below 32 GB are usually based on the SDHC specification, while larger capacities require SDXC. Please check your SD card readers or devices if these can support SDXC.