SD cards, or Secure Digital cards, are a type of non-volatile memory card used for storing digital information. They were introduced in 1999 by Panasonic, SanDisk and Toshiba, with the name deriving from the Secure Digital Music Initiative that aimed to create a secure means of distributing music. Over the years, SD cards have become one of the most common standards of removable flash storage for consumer electronics. [1]
SD cards are widely used in digital cameras, camcorders, media players, mobile phones, video game consoles, PDAs, computers, tablets, and many other consumer electronics. They are a practical way of expanding the memory storage capabilities of various devices in a portable and re-writable format. When first introduced, SD card capacities ranged from 8-128MB. But over time capacities have grown enormously, reaching up to 1TB for the largest SD cards available today. This evolution in capacity has enabled people to store vastly larger amounts of photos, videos, music, documents and other data on these removable memory cards. [1]
Current Maximum SD Card Sizes
There are currently three SD card formats that support different maximum capacities:
- SD (Standard Capacity) – Supports up to 2GB
- SDHC (High Capacity) – Supports from 4GB up to 32GB
- SDXC (Extended Capacity) – Supports from 64GB up to 2TB
The SD card formats are backwards compatible, meaning SDHC cards work in SD card slots and SDXC cards work in SDHC and SD slots. But the reverse is not true – SD cards don’t work in SDHC or SDXC slots.
The different formats use different filesystems to support the higher capacities. SD uses FAT12 or FAT16. SDHC uses FAT32 and SDXC uses exFAT to allow capacities of 64GB and higher.
So in summary, the current maximum capacities are:
- SD – up to 2GB
- SDHC – up to 32GB
- SDXC – up to 2TB
1TB SD Cards
In recent years, some SD card manufacturers have demonstrated prototype 1TB SD cards, but they are not yet commercially available to consumers. In 2016, SanDisk unveiled a 1TB SD card prototype at the Photokina trade show [1]. Similarly, in 2019 Lexar displayed a 1TB SD card prototype at the Consumer Electronics Show [2]. However, these prototypes are primarily for demonstrating technological capabilities and have not been released as retail products.
The main challenges in developing a 1TB SD card are achieving the required storage density while maintaining the card’s small physical size, speed, reliability, and affordability. Although 1TB prototype cards have been shown, most experts believe commercially available 1TB SD cards are still a few years away from hitting the mainstream consumer market.
Factors Influencing Maximum Size
There are several key factors that influence the maximum size of SD cards available on the market:
Manufacturing challenges with high capacities – Producing SD cards with very high capacities presents difficulties for manufacturers. Extremely dense NAND flash memory chips are required, along with advanced controller technology. This increases costs and complexity significantly above smaller capacities. There are also yield issues when producing cutting-edge high density chips [1].
Market demand and use cases – Most consumer devices have limited need for huge SD card capacities. Smartphones generally have 64-512GB of internal storage these days. Digital cameras rarely need more than 1TB cards. There is not yet massive consumer demand for multi-terabyte SD cards. Industrial and specialized use cases requiring huge capacities are a niche market [2].
Compatibility considerations – SD cards have size limitations imposed by host devices like cameras and smartphones. The SD card spec has increased over time from SD to SDHC to SDXC to support larger sizes. But older devices may only be compatible with lower capacity cards. There’s little incentive for manufacturers to make SD cards larger than what devices support [3].
Uses Cases for Large SD Cards
Large capacity SD cards have become incredibly useful for professionals and hobbyists who need substantial portable storage. The key uses cases that benefit from 1TB+ SD cards include:
Professional and Industrial Photo/Video Storage
Photographers and videographers who shoot high resolution raw images or 4K/8K video require vast amounts of storage space. A 1TB SD card can hold thousands of raw photos or hours of ultra high definition footage in a compact form factor that’s easy to offload from cameras.
Industries like TV/film production, surveillance, engineering, science, and medicine capture huge video files and image sets for which high capacity SD cards offer reliable portable storage.
Gaming Storage Expansion
Modern video game consoles and handheld gaming devices allow storage expansion via SD cards. With game install sizes ballooning up to 100+ GB, high capacity 1TB+ SDXC cards enable gamers to store sizable libraries without constantly deleting and re-downloading games.
Drones and Cameras
Drones used for aerial photography, videography, surveying, and inspection generate massive piles of imagery and mapping data. Similarly, network IP cameras used for security, traffic monitoring, and commercial applications produce huge video streams. 1TB+ SD cards give these devices ample onboard storage for capturing hours of continuous footage.
SD Card Format Comparisons
There are three main SD card formats to consider – SD, SDHC, and SDXC. Each format has differences in speed, storage capacity, and device compatibility that are important to understand when selecting an SD card.
The original SD card format supports capacities up to 2GB and read speeds up to 25MB/s. SDHC (Secure Digital High Capacity) cards support capacities between 4GB and 32GB with read speeds up to 104MB/s. SDXC (Secure Digital eXtended Capacity) cards support capacities above 32GB up to a maximum of 2TB with ultra fast read speeds over 300MB/s.
In terms of compatibility, SDHC and SDXC cards will work in devices designed for the standard SD format. However, standard SD cards will not work properly in devices designed for SDHC and SDXC. When selecting an SD card, it’s important to check which formats your device supports to avoid any issues.
SDXC cards also exclusively use the exFAT file system, while SD and SDHC cards use the FAT32 system. exFAT supports larger individual file sizes over 4GB, while FAT32 limits individual files to 4GB. This makes exFAT better suited for very high resolution photos and large video files.
For most users, SDHC and SDXC cards offer the best combination of storage capacity, speed, and compatibility with modern devices. When formatting SD cards, the most widely compatible option is FAT32, though exFAT enables larger files for advanced users.
Future Outlook
Industry experts predict that SD card capacities will continue to increase dramatically in the coming years. With the introduction of new technologies like SDUC, maximum capacities of 1TB-2TB are expected in the near future.
Some key advancements that will enable larger SD card sizes include:
- 3D NAND flash memory – With stacking cells in three dimensions instead of two, 3D NAND allows for higher densities and capacities in the same footprint.
- Quad-level cell (QLC) NAND – QLC NAND can store 4 bits per cell compared to the standard 3 bits, increasing overall densities.
- Shingled magnetic recording (SMR) – SMR overlaps tracks on a disk similar to roof shingles, enabling higher capacities.
Manufacturers like SanDisk and Samsung continue to invest heavily in NAND fabrication methods to enable larger wafers and dies. This directly translates to SD cards with higher capacities. New standards beyond SDXC are also being developed to support capacities over 2TB.
Consumers can expect SD card sizes to hit 2TB in the mainstream market within the next 2-3 years. Some forecasts predict capacities up to 128TB in the longer-term as technologies like SDUC mature. The future looks bright for extremely large and dense SD cards!
Recommendations
When buying an SD card, it’s important to consider your intended use case and storage needs. Here are some tips for choosing the right capacity card:
For everyday photo and video recording on a smartphone or basic camera, a 32GB or 64GB card should suffice. This provides storage for thousands of photos and hours of 1080p video (1).
For advanced/professional photography and 4K video recording, a 128GB or 256GB card is recommended to store RAW images and high-resolution footage. Consider 512GB or 1TB cards if you’ll be recording a lot without offloading (2).
For gaming consoles, a 512GB card provides ample storage for dozens of games, though casual gamers may be fine with 256GB. Hardcore gamers who download many large titles may want 1TB (1).
When in doubt, buy more capacity than you need to allow room for growth. The cost per gigabyte drops at higher capacities. It’s better to have too much than too little storage.
Summary
In summary, the largest commercially available SD card currently is 1TB. SD cards up to 2TB are technically possible but have not yet been produced. The maximum size of SD cards depends on a number of factors like the SD format, camera megapixels, 4K video recording needs, and expanding use cases requiring large portable solid state storage. While most consumer devices today don’t need more than 512GB, high-end DSLR cameras can benefit from 1-2TB cards. And as technology continues advancing, even larger capacity SD cards will likely emerge. So in the future, 2TB+ SD cards will become more commonplace.
The key factors influencing SD card capacities are the type of NAND flash memory, the SD card formatting, and the market demand for ever-larger storage on tiny SD card chips. As manufacturers continue innovating with triple-level-cell and quadruple-level-cell NAND, and new SD card specifications boost theoretical maximums, maximum SD card sizes will steadily increase over time. Consumers will be the ultimate beneficiaries of this capacity growth.
References
SD Association. “SD Card History.” https://www.sdcard.org/consumers/history/. Accessed March 13, 2023.
Panasonic. “The world’s first 1TB SD card.” https://news.panasonic.com/global/topics/2020/72730.html. Accessed March 13, 2023.
Kingston. “Everything You Want to Know About SD Memory Cards.” https://www.kingston.com/unitedstates/us/memory-cards/sd-memory-cards. Accessed March 13, 2023.
SanDisk. “A History of Storage.” https://www.sandisk.com/about/history-of-storage. Accessed March 13, 2023.
Tom’s Hardware. “SD Express: Up To 985 MB/s And Beyond 2TB SDXC.” https://www.tomshardware.com/news/sd-express-sdxc-sdhc,37590.html. Accessed March 13, 2023.
