Ruigu Electronic

Unlocking Speed: The Future of SD Cards with SD Express

2025-12-01

SD Express is a next-generation SD memory card standard launched by the SD Association. Its core lies in introducing the PCIe and NVMe architectures to break the speed bottleneck of traditional SD cards, adapting to high-performance storage scenarios such as 8K video shooting and large game loading, while maintaining backward compatibility. Its relevant specifications are continuously upgraded with technological iteration, detailed as follows:

1. Core Technology and Speed Specifications

Underlying Architecture: Abandoning the data transmission bus of traditional SD cards, it adopts the PCIe (PCI Express) interface paired with the upper-layer NVMe protocol—a technical combination commonly used in mainstream high-speed solid-state drives (SSDs), enabling efficient memory access and data transmission. Different specification versions correspond to different PCIe standards: for example, under the SD 7.0 specification, SD Express uses a PCIe 3.0×1 interface with a transmission rate of 985 MB/s; the SD 8.0 specification upgrades the PCIe version to 4.0, with a single-lane rate of up to 2 GB/s and a maximum rate of nearly 4 GB/s (about 3940 MB/s) with dual lanes (PCIe 4.0×2).
Hardware Adaptation Differences: Single-lane SD Express memory cards have two rows of pins, while dual-lane versions feature three rows of pins to meet higher transmission requirements. They also maintain compatibility with the physical form factor of traditional SD cards, facilitating adaptation by device manufacturers.

2. Derivative Versions and Device Compatibility

Corresponding Micro Cards: There is a dedicated microSD Express version, a miniature form of SD Express, adapted for small devices such as smartphones, drones, and handheld game consoles. For instance, microSD Express cards from brands like Lexar and SanDisk offer sequential read speeds of up to 900 MB/s and 880 MB/s respectively, and are compatible with devices such as the Nintendo Switch 2.
Backward Compatibility: Both full-size SD Express and microSD Express are backward compatible with older interface devices such as UHS-I and UHS-II. However, when used on older devices, the speed is limited to the maximum level of the corresponding interface, ensuring the usability of users’ existing devices.

3. Typical Application Scenarios

Audio-Visual Creation: Its ultra-high transmission speed can meet the needs of 8K video recording and continuous shooting of RAW format photos, enabling fast storage of large-capacity audio-visual files and avoiding shooting freezes caused by insufficient storage speed.
Gaming Industry: Adapted for game consoles such as the Nintendo Switch 2, it can be used as expandable storage to load large games, significantly reducing game loading time and improving gaming smoothness. Previously, Lexar’s 1TB microSD Express card sold out in the Japanese market following the release of the Nintendo Switch 2.
Industrial and Specialized Scenarios: It also meets the high-speed data read/write requirements of scenarios such as IoT devices, in-vehicle systems, and AI edge computing. For example, in-vehicle devices can quickly store driving images and navigation data, and IoT devices can adapt to high-frequency sensor data transmission.

4. Market and Product Status

Currently, mainstream storage brands such as SanDisk, Apacer, and Lexar have launched SD Express or microSD Express products, with capacities covering multiple specifications from 128GB to 1TB. Some brands have also launched dedicated card readers; for example, Lexar’s dedicated card reader uses a USB 10Gbps interface, supports the PCIe 3.0×1 protocol, and is equipped with active cooling to ensure stability during high-speed transmission. Most of these products feature water resistance, shock resistance, and high/low temperature resistance, adapting to complex usage environments.