Storage for SBCs: which media works best

Single Board Computers (SBCs) have revolutionized embedded computing, offering powerful capabilities in compact, low-power packages. However, unlike traditional desktops with their readily swappable hard drives, storage on SBCs comes in various forms, each with its own trade-offs in terms of performance, cost, and reliability. Understanding these differences is crucial for any project, from a simple home automation hub to a demanding edge AI device.

microSD cards: the ubiquitous entry point

For many, the microSD card is the first encounter with SBC storage. Its low cost and universal compatibility with most boards, including the popular Raspberry Pi series, make it an accessible entry point. Installing an operating system like Armbian is as simple as flashing an image to the card.

However, microSD cards have significant limitations. They are generally the slowest of the common SBC storage types, with varying read/write speeds depending on the card's class. More critically, they are less resilient to the constant read/write cycles that an operating system demands. This means they can degrade and fail relatively quickly, particularly in applications with frequent logging or database operations. For casual use, a good quality A1 or A2-rated microSD card is often sufficient, but for anything critical or performance-sensitive, alternatives are strongly recommended.

eMMC: the embedded workhorse

Embedded MultiMediaCard (eMMC) represents a significant step up from microSD cards. Often found soldered directly onto the SBC's board, or available as a module, eMMC storage integrates the flash memory and a dedicated controller into a single chip. This integrated controller handles wear-leveling and error correction, significantly improving both performance and endurance compared to raw microSD cards.

eMMC typically offers faster sequential read and write speeds, often comparable to older SATA SSDs. This translates to quicker boot times, snappier application loading, and overall better system responsiveness. Its embedded nature also provides a more robust and physically secure storage solution, making it ideal for industrial or high-reliability applications where vibration or accidental removal are concerns. While more expensive than microSD, the enhanced durability and performance often justify the cost for more demanding projects.

NVMe: the speed demon

For the ultimate in SBC storage performance, Non-Volatile Memory Express (NVMe) reigns supreme. With the introduction of PCIe interfaces on more advanced SBCs, such as the Raspberry Pi 5, NVMe SSDs have become a game changer. These drives communicate directly with the CPU via the high-speed PCIe bus, bypassing the bottlenecks of traditional storage interfaces.

NVMe offers dramatically faster read and write speeds often an order of magnitude or more greater than eMMC or microSD cards. This is critical for applications that involve large data transfers, intensive database operations, or running complex software that constantly accesses storage. Think of a local AI inference server, a high-throughput network-attached storage (NAS) device, or a system requiring rapid boot-up and application launch. While NVMe drives and the necessary adapters (often HATs for Raspberry Pi) add to the overall cost, the performance gains can be transformative for projects where speed is paramount.

Choosing the right storage for your SBC project means balancing budget, performance requirements, and reliability needs. While microSD cards offer an easy entry, eMMC provides a more robust and performant solution for general use, and NVMe delivers uncompromised speed for the most demanding applications. Understanding these distinctions ensures your SBC project has the solid foundation it needs to succeed.