Core Viewpoint - The article discusses the evolution and current state of storage devices, particularly focusing on SD cards and CFE cards, highlighting their specifications, classifications, and recommendations for usage in various devices [3][29]. Group 1: SD Cards - SD cards, developed in 1999 by Panasonic, Toshiba, and SanDisk, have evolved into a family of products with various capacities and speed classifications [3][5]. - The capacity levels for SD cards are categorized into four types: SD (up to 2GB), SDHC (2GB to 32GB), SDXC (32GB to 2TB), and SDUC (2TB to 128TB) [5]. - SD cards are classified based on write speed into three standards: Speed Class (C), UHS Speed Class (U), and Video Speed Class (V), with specific minimum write speeds ranging from 2MB/s to 90MB/s [7][8]. - UHS levels (UHS-I, UHS-II, UHS-III) indicate bus speed, with theoretical maximum speeds of 104MB/s, 312MB/s, and 624MB/s respectively [8][11]. - Manufacturers may label speeds using X ratings, where 1X equals 150KB/s, allowing for easy conversion to MB/s [13]. Group 2: TF Cards - TF cards, originally known as TransFlash cards, are smaller than SD cards and share similar speed classifications [15][17]. - TF cards also include an A rating for application performance, with A1 and A2 levels indicating different IOPS performance for running apps directly from the card [17][18]. Group 3: CFE Cards - CFE cards, based on PCIe and NVMe standards, offer high performance suitable for high-end cameras, with maximum read/write speeds of 2000MB/s for CFE-A and 4000MB/s for CFE-B [20][22]. - CFE cards are categorized by VPG levels, ensuring minimum sustained write speeds of 200MB/s to 400MB/s, with future standards promising even higher speeds [22][23]. Group 4: Recommendations for Use - For entry-level cameras, a V30 SD card with a capacity starting at 64GB is recommended, while higher-end models should consider CFE cards of 256GB or more for optimal performance [24][26]. - High-end cameras require CFE cards to fully utilize their capabilities, and users are expected to be knowledgeable about their specific storage needs [27]. - For devices like drones and action cameras, TF cards of at least 128GB with U3 and A2 ratings are suggested for efficient 4K recording [27][30].