Secure Digital (SD) Cards

Make sure you get the MICRO card if you do not have an SD Adapter

SD standards are available in three capacities: SD standard, SDHC standard and SDXC standard.

Each of these formats has a variety of speed options, giving product developers the flexibility they need to create products for a variety of needs.

The standards have the broad interoperability and compatibility needed to ensure support between multiple devices and for future applications.

An Introduction to SD Standards

SD standards enable manufacturers to deliver high-performance products that enhance the experience of millions of people every day who listen to music, record videos, take photos, save data and use a mobile phone.

As the industry standard, the SD standard is utilised across multiple market segments of the portable storage industry,including mobile phones, digital cameras, MP3 players, personal computers, tablets, printers, car navigation systems,electronic books, and many other consumer electronic devices.

SD: What Does It Mean?

Let’s start by breaking down the blanket term that is “SD,” short for Secure Digital, which is a memory card format developed by the SD Association.

SD Association | The SD AssociationSD Association | The SD Association

SD Association Website

SD memory cards have four SD standards that feature four capacities.

The four SD standards are:

Type	Capacity
SD	2GB and under
SDHC	More than 2GB, up to 32GB
SDXC	More than 32GB, up to 2TB
SDUC	More than 2TB, up to 128TB

SD Card Labeling and Specifications

One of the great things about SD cards is the amount of information that’s provided on the front of the card, so you can expect to find not only SD, SDHC, or SDXC, but also the card’s specific storage capacity.

Maximum Memory

There is a maximum SD card size that can be used with the Raspberry Pi 5.

Here are some user views:

User Experience

One user mentions using a 128GB SD card on the Pi 5 without issues, while another clarifies that they have successfully used 128GB cards on Pi 4 models, debunking the claim that the maximum limit for Pi 4 is 64GB.

Known Compatibility

Another contributor states that the Raspberry Pi 5 is known to work with 500GB cards and is thought to work with at least 1TB. The SDXC standard, which Raspberry Pi supports, goes up to 2TB.

Raspberry Pi Engineer's Input

A Raspberry Pi engineer suggested that the theoretical maximum SD card size is 2TB, although they personally haven't tested cards of that capacity. They confirmed that 512GB cards are known to work.

Alternative Storage Solutions

It's mentioned that while large SD cards can be used, using an SSD via a USB connection is a faster, cheaper, and more reliable storage solution for the Raspberry Pi.

Practical Advice: While Raspberry Pis can technically support very large SD cards, USB flash drives or SSDs offer better value and performance for extensive storage needs.

SD Cards for Raspberry Pi

This design choice helps keep the Raspberry Pi's cost low.

While it's possible to boot a Raspberry Pi 4 using a USB SSD or Flash Drive, which can offer faster performance, microSD cards remain a popular, more straightforward, and cost-effective storage solution.

For Raspberry Pi users, 32GB microSD cards are recommended as they provide ample storage for most applications without being significantly more expensive than smaller capacity cards.

When selecting a microSD card for a Raspberry Pi, it's essential to consider performance and reliability, especially with the Raspberry Pi 5 supporting SDR104 microSD cards, promising improved performance.

SDXC Memory Cards: Massive Storage

The SDXC (Secure Digital Extended Capacity) memory card standard is a significant evolution in the storage technology used in a wide array of electronic devices.

Increased Storage Capacity

The SDXC standard extends the maximum storage capacity of SD cards from the 32GB limit seen in SDHC (Secure Digital High Capacity) cards up to a staggering 2 TB (terabytes).

This massive increase in storage allows users to store high-resolution photos, 4K and 8K videos, extensive music libraries, and other large files more comfortably, without the need to frequently swap out cards.

File System Change

SDXC cards use the exFAT (Extended File Allocation Table) file system instead of the FAT32 system used in SDHC cards. The exFAT system is optimized for flash memory like SD cards, supporting larger files (over 4GB) and providing better storage efficiency and faster access to large amounts of data.

What is FAT?

The "FAT" in FAT32 and exFAT stands for "File Allocation Table," which is a file system used for organising and managing files on storage devices.

File Allocation Table (FAT)

FAT is one of the oldest and most widely compatible file systems.

It maintains a table (the FAT) that acts as an index to locate different pieces of a file stored across a storage device. When a file is stored, it may not be stored in contiguous sectors on the disk; the FAT keeps track of all these fragments, ensuring that the system can efficiently assemble and access the complete file.

FAT32

This is an extension of the original FAT system, introduced to overcome the limitations of previous versions (like FAT16).

FAT32 supports larger disk sizes and files than FAT16 but has a maximum file size limit of 4 GB and a maximum volume size limit of 16 TB (though in practice, this is often limited to 2 TB by operating systems). FAT32 is highly compatible across different operating systems, making it a versatile choice for removable storage.

exFAT (Extended File Allocation Table)

Introduced by Microsoft, exFAT is a modernised version of FAT32, designed to address some of its limitations, particularly for flash memory devices like SD cards and USB flash drives. Here are the key benefits of exFAT over FAT32:

• Support for Larger Files: exFAT can handle files larger than 4 GB, which is a significant advantage for users who need to store high-resolution videos or large datasets.

• Efficient Storage: exFAT uses a more modern allocation system, which reduces the overhead of managing file and directory entries, allowing for more efficient use of disk space, especially with very large files.

• Faster Access: The optimisations in exFAT can lead to faster access times for files, particularly noticeable with large files or when dealing with a large number of small files.

• Compatibility: While not as universally supported as FAT32, exFAT is compatible with most modern operating systems, including Windows, macOS, Linux (with additional software), and various devices, making it suitable for removable media.

Usage in SDXC Cards

SDXC cards use exFAT because these cards are designed to support capacities from 32 GB up to 2 TB, and users are likely to store files larger than 4 GB.

By using exFAT, SDXC cards provide users with the flexibility to store large files efficiently while maintaining relatively wide compatibility with modern devices and computers.

In summary, the transition from FAT32 to exFAT for SDXC cards is a response to the growing need for storing larger files and making better use of the advanced storage capacities of modern flash memory devices.

Enhanced Speed with UHS

Some SDXC cards are equipped with Ultra High Speed (UHS) bus interfaces, such as UHS-I or UHS-II, which significantly increase data transfer rates compared to non-UHS cards.

UHS-I can provide speeds up to 104 MB/s, while UHS-II can go up to 312 MB/s.

This is crucial for tasks that require quick read/write operations, such as recording 4K or 8K video, capturing burst photos in high-resolution, or transferring large files between devices.

Compatibility

SDXC cards are designed to be backward compatible with devices that support SDHC cards, although the device needs to be SDXC-compatible to utilize the full capacity and speed benefits of SDXC cards. It's important to check the device's specifications to ensure compatibility with SDXC cards, especially for older devices.

Application in Various Devices: The increased storage and speed capabilities of SDXC cards make them ideal for a range of electronic devices. For instance:

• Digital Cameras and Camcorders: Store hours of high-definition video or thousands of high-resolution images without worrying about running out of space.

• Tablets and Smartphones: Expand the storage for apps, games, photos, and videos, enhancing the device's usability and entertainment potential.

• HDD Recorders/Players and TVs: Record and playback hours of HD or 4K content without needing frequent data offloads.

• Personal Navigation Devices (PNDs): Store extensive map data and multimedia content for enhanced navigation and entertainment during travels.

• Mobile Phones: Expand storage for media, apps, and other data, providing flexibility and convenience for users.

Data Management and Security

With the vast storage capacities of SDXC cards, efficient data management becomes crucial.

Users should implement regular backups and data organisation strategies to ensure data integrity and accessibility.

Additionally, the exFAT file system supports access controls and ownership, providing a layer of security for sensitive files.

In summary, SDXC memory cards offer a substantial leap in storage capacity and speed, enhancing the digital experience for consumers by enabling extensive media libraries, high-speed data transfers, and greater flexibility in how we use our electronic devices.

Fastest microSD Cards for Raspberry Pi 5

1st Place: Amazon Basics (64GB)

Our old friend, the Amazon Basics microSD card, sits at the top of yet another “Best Of” test, only falling behind on the sequential read speeds, where the Transcend (32GB) card hit an impressive 78.46MB/s. The 128GB model was very close, though I feel it’s a little unfair to put them both up here so based on value, I’ve selected the 64GB option as my number 1.

2nd Place: Intenso (64GB)

Taking an overall 2nd place thanks to great random read/write speeds, we have the Intenso (64GB) microSD card. It’s not the most well-known brand, but it’s holding its own here!

3rd Place: Transcend (32GB)

It was super close between the Transcend (32GB) and Samsung PRO Plus (128GB) for 3rd place but thanks to the Transcend’s slightly higher random write results, I’ll go with that. It was extremely close though and if you trust Samsung as a brand over Transcend, it may still be your choice.