CFAST and CF cards are both memory cards used in digital devices, but they differ in interface, speed, size, compatibility, and price. CFAST cards use a faster Serial ATA (SATA) interface, have higher transfer speeds (up to 600 MB/s), and are slightly larger than CF cards, which use a Parallel ATA (PATA) interface and have lower transfer speeds (around 160 MB/s). CFAST cards are more suitable for high-end professional devices but are generally more expensive, while CF cards are more widely compatible with older devices.