Class 10 SD cards have the highest performance. The slot on Macs accept cards that are either Standard SD (Secure Digital) up to 4 GB, SDHC (Secure Digital High Capacity) 4 GB to 32 GB, and SDXC (Secure Digital eXtended Capacity) cards in 32, 64, or 128 GB sizes. Some connect internally via USB, others interface directly with the PCI bus for faster performance. Combining both speed AND high capacity - those owning select models of Mac mini, Apple MacBook Pro and Air, as well as Aluminum iMac models may have a built-in SD memory card slot reader.
