SDXC (Secure Digital Extended Capacity) and exFAT (Extended File Allocation Table) refer to two different things. SDXC is a type of SD memory card that can store up to 2TB of data. exFAT is a file system that was introduced by Microsoft to support larger storage devices.
So in short, no – SDXC and exFAT are not the same thing. SDXC is a type of SD memory card, while exFAT is a file system. However, there is a relationship between the two. Many SDXC cards are formatted with the exFAT file system in order to support their large storage capacities.
What is SDXC?
SDXC stands for Secure Digital Extended Capacity. It is a type of SD memory card that was introduced in 2009 by the SD Association.
The key features of SDXC cards include:
– Storage capacity up to 2TB – Compared to regular SD cards which max out at 32GB and SDHC cards which go up to 32GB, SDXC cards can store huge amounts of data. The 2TB limit is a theoretical maximum – currently the largest SDXC cards available are 1TB.
– Based on the exFAT file system – To support the massive storage capacities, SDXC cards are formatted using the exFAT file system rather than the traditional FAT32 system used by SD and SDHC cards. exFAT allows for individual files larger than 4GB.
– Backwards compatible – Despite the difference in file system, SDXC cards are backwards compatible. They can be used in older SD host devices, although obviously the capacity over 32GB may not be accessible.
– High speed data transfer – SDXC cards have to meet a minimum speed class rating of Class 10 which guarantees a minimum sustained write speed of 10MB/s. Many new SDXC cards are even faster with UHS-I interfaces.
– Used for high resolution photos, 4K/8K video – The huge storage capacity makes SDXC cards well-suited for media creation. High resolution RAW photos, 4K and 8K video take up a massive amount of space.
So in summary, SDXC is not a file system itself. It is a type of SD card that can store up to 2TB and uses the exFAT file system to support the large capacity. All SDXC cards have to meet the standards set by the SD Association.
What is exFAT?
exFAT (Extended File Allocation Table) is a file system introduced by Microsoft in 2006. It was added as an optional file system to Windows Vista and Windows Server 2008.
Here are some key attributes of the exFAT file system:
– Supports large storage devices – exFAT can support volumes up to 128 petabytes in size. This is significantly larger than the 4GB limit of FAT32 which made it unsuitable for larger SD cards.
– Stores large individual files – Whereas FAT32 limited individual files to 4GB in size, exFAT supports files over 4GB. Very useful for large media files.
– Faster than NTFS – exFAT is lighter weight than NTFS (New Technology File System) which makes it faster when writing and reading data. This makes it good for flash memory cards which need high speed data transfers.
– Used on high capacity SD cards – Given its large volume and file size limits, exFAT is used by high capacity SDXC cards to support up to 2TB of storage.
– Also used on USB flash drives – exFAT is often used instead of FAT32 on USB flash drives 64GB or larger. Again this allows support for huge storage capacities and large files over 4GB in size.
– Supported by modern operating systems – Windows, macOS and Linux all have support for exFAT built in or available to install. This gives exFAT wide compatibility across devices.
So in summary, exFAT is a file system optimized for large storage devices like high capacity SD cards and USB flash drives. It removes limits on volume and file sizes that restricted previous file systems like FAT32.
Relationship Between SDXC and exFAT
Although SDXC and exFAT refer to different things, they are very closely related in practice when it comes to high capacity SD cards.
Here is an overview of the relationship:
– SDXC defines card capacities up to 2TB – The SDXC specification defines SD cards with capacities ranging from 32GB up to 2TB. Without the SDXC standard, SD cards would be limited to 32GB maximum.
– SDXC requires minimum write speeds – To ensure proper performance for large data, the SDXC specification requires cards have minimum sequential write speeds of 10MB/s.
– exFAT does not have volume limits – The exFAT file system has no volume limit and can address up to 128PB. This is necessary to store up to 2TB on one SD card.
– exFAT supports files larger than 4GB – SDXC cards over 32GB must hold files larger than 4GB. This is only possible with exFAT rather than FAT32.
– SDXC cards are formatted as exFAT – While not a technical requirement, in practice virtually all SDXC cards over 32GB are pre-formatted with the exFAT file system to meet capacity and speed needs.
– Older devices may not support exFAT SDXC – If older devices do not support exFAT, capacities over 32GB on SDXC cards may not be readable even though the cards are backwards compatible.
So in summary, although SDXC and exFAT are different things, they complement each other when it comes to high capacity SD cards. The SDXC specification requires cards with very large storage. To achieve this, the exFAT file system is used due to lack of limits on volume and file sizes.
Advantages of SDXC Cards
SDXC cards offer a number of benefits, especially for people who need high storage capacity:
– Huge storage capacity – SDXC supports capacities up to 2TB. This is a gigantic amount of storage that can hold hundreds of thousands photos or hours of video.
– Ideal for media files – The large capacity is perfectly suited for storing lots of high resolution photos and HD, 4K or 8K video. SDXC is very popular with photographers and videographers.
– Reliable and durable – SD cards have proven themselves to be reliable and durable storage media, even in demanding conditions. The SD Association certifies SDXC cards to ensure quality.
– Small physical size – Even though SDXC cards can store massive amounts of data, the physical card size remains very compact. The convenient size makes them highly portable.
– Backwards compatible – SDXC cards can be used in older SD host devices, although capacities above 32GB may not be accessible in devices lacking exFAT support.
– High transfer speeds – SDXC cards are required to support minimum write speeds of 10MB/s. Many newer cards are even faster, with transfer speeds over 90MB/s.
– Widely supported – SDXC is supported across many devices from cameras to phones to computers. Support for exFAT is also widespread.
So for anyone needing reliable and portable storage for large media files, SDXC cards are a great choice. The combination of huge capacity, compact size and lightning speed makes them very versatile.
Disadvantages of SDXC
However, there are some downsides or limitations to consider with SDXC cards:
– More expensive per gigabyte – Although prices fluctuate, SDXC cards are generally more expensive per gigabyte compared to normal SD cards or hard drives. The massive capacity comes at a premium.
– Overkill for smaller storage needs – If you only need to store a few gigabytes, an SDXC card may be overkill. The extra capacity will go to waste.
– exFAT less widely compatible than FAT32 – Although support for exFAT is common, there are still some older devices that may only work with FAT32 volumes.
– Easy to accidentally format – It’s possible to accidentally format extra large SDXC cards down to smaller capacities if not paying close attention. This makes the unused capacity unusable.
– Increased risk from corruption – The more data that is stored on a card, the more damaging corruption can be. Corruption on a 1TB SDXC could mean losing hundreds of gigabytes of data.
– Physical size limitations remain – Even though capacities are huge, the tiny physical size of SD cards makes them easier to misplace and potentially lose.
So SDXC cards may not make sense for all use cases, especially if storage needs are small. The super large capacities come with some tradeoffs compared to lower capacity options.
Use Cases for SDXC Cards
Here are some of the most common use cases where SDXC cards really shine:
Photography
SDXC cards are very popular for photography given their large capacities to store high resolution photos. A 1TB SD card could store over 100,000 RAW images from a high megapixel DSLR camera. The compact size also makes them convenient for taking out in the field.
Videography
The ability to store hours of HD, 4K or 8K video on a portable SD card makes SDXC ideal for videographers and filmmakers. Cards with very high read/write speeds are crucial to support high bitrate video recording.
Gaming
Some gaming devices like Nintendo Switch use SDXC cards to expand storage for game downloads and save data. Large SDXC cards allow packing in dozens of games.
Drones
Many camera drones rely on SD cards for storing captured aerial footage. SDXC cards allow fitting more high resolution video given the limited onboard storage on most drones.
Laptop/PC
SDXC cards can supplement limited internal storage on laptops and desktop PCs. With capacities up to 1TB, they can easily hold entire media libraries for access across different devices.
Raspberry Pi
For projects involving Raspberry Pi single board computers, SDXC cards provide ample storage for the OS, applications, media files and other data storage needs.
Dashcams & Action Cams
Loop recording dashcams and action cameras that capture lots of driving or adventure footage can make good use of high capacity SDXC cards to maximize recording time before needing to offload footage.
So in summary, SDXC cards are well suited for a variety of primarily media-focused use cases that require storing very large files and maximizing recording time.
Compatibility Considerations
When adopting high capacity SDXC cards, it’s important to ensure compatibility with your devices:
– Make sure devices support SDXC – Most modern cameras, phones, PCs and other devices support SDXC, but older devices may max out at 32GB SDHC.
– Confirm exFAT support – To utilize full SDXC capacity over 32GB, the device needs exFAT support due to FAT32 limits. Some only support FAT32.
– Check read/write speeds – Devices need to support minimum sequential speeds of 10MB/s, but faster cards may require UHS-I or UHS-II compatibility.
– Consider SD card generations – Newer SD specifications like UHS-II offer faster speeds but require host device support. Avoid speed mismatches.
– Compare manufacturer recommendations – Check documentation and specs from manufacturers on recommended memory cards to choose optimal cards.
– Test thoroughly before relying on card – When using SDXC cards in critical applications, thoroughly test to confirm performance and compatibility before fully relying on the card.
Taking these precautions helps avoid compatibility issues. In general, SDXC cards are designed to be backwards compatible, but practical capacity and speed limitations can come into play depending on the host device capabilities.
SDXC Card Speed Classes
In addition to storage capacity, SDXC cards are grouped into speed classes signifying minimum performance thresholds. Faster cards allow capturing more high resolution photos/video per second. Here are some key SDXC speed classes:
Class 10 – Minimum sequential write speed of 10MB/s. All SDXC cards must meet this level.
UHS Speed Class 1 (U1) – Minimum sequential write speed of 10MB/s (same requirement as Class 10).
UHS Speed Class 3 (U3) – Minimum sequential write speed of 30MB/s. Offers triple the speed of Class 10 cards.
Video Speed Class 30 (V30) – Minimum sequential write speed of 30MB/s. Used for recording high resolution video like 4K and 8K.
Video Speed Class 60 (V60)/Class 90 (V90) – Even faster video oriented cards with minimum sustained write speeds of 60MB/s and 90MB/s respectively.
Faster SDXC cards require host devices capable of keeping up with UHS bus interfaces. A Class 10 card may only achieve Class 10 speeds in a device lacking UHS-I support. When recording video, matching the card Speed Class to the camera/device capabilities is crucial.
Top SDXC Card Manufacturers
Here are some of the top brands for quality SDXC memory cards across different performance levels:
| Brand | Speed Classes |
|---|---|
| SanDisk | UHS-I, UHS-II, V30, V60, V90 |
| Sony | UHS-I, UHS-II, V30, V60, V90 |
| Samsung | UHS-I, UHS-II, V30 |
| Lexar | V30, V60, V90 |
| PNY | UHS-I, V30 |
| Transcend | UHS-I, V30 |
| Kingston | UHS-I, V30 |
SanDisk and Sony in particular offer a wide range of UHS-II and V90 cards meeting the highest speed class ratings, but other brands offer great performing SDXC options as well. It’s best to compare benchmarks for factors like sequential read/write speeds when buying high speed cards.
SDXC vs. microSDXC
SDXC cards also come in a microSDXC variant. As the name suggests, microSDXC cards are a smaller physical size:
SDXC
– 32mm x 24mm x 2.1mm
– Weighs ~2g
– Used in full-size SD card slots
microSDXC
– 15mm x 11mm x 1mm
– Weighs ~0.5g
– Used in microSD card slots
MicroSDXC cards offer all the same capacities as full-size SDXC cards, just in a much smaller physical footprint. The small size does entail some tradeoffs though:
– Durability – MicroSD cards are easier to lose and more prone to physical damage due to their tiny size.
– Speed – MicroSDXC maximum speeds top out around ~100MB/s whereas full-size SDXC can exceed 300MB/s.
– Price – Given higher manufacturing costs, microSDXC cards tend to cost more than equivalently sized SDXC cards in terms of $/gigabyte.
So microSDXC provide a compact option when size is critical, like in phones and action cams. But full-size SDXC can be more robust and cost effective when size isn’t an issue.
SDXC Card Storage & Care
To get the most out of SDXC cards and maximize their lifespan, proper storage and care is important:
– Use protective case – Store the SD card in a rigid plastic case when not in use to avoid bending or scratches.
– Avoid magnets – Keep SD cards away from magnets or magnetic fields that can potentially corrupt data.
– Handle with care – Be gentle to avoid exerting pressure/bending when handling the card to prevent physical damage.
– Keep dry – Protect SD cards from exposure to liquids which can short circuit and destroy them.
– Don’t touch contacts – Avoid touching the golden contacts on the card which can transfer oils and residue leading to corrosion.
– Eject properly – Always properly eject the card before removing from devices to avoid potential data loss or corruption.
– Backup irreplaceable data – As SD cards can unexpectedly fail, keep backups of your most important photos/videos on other storage media.
Proper care and handling will help extend the usable life of SDXC cards. But all storage media is susceptible to eventual failure, so backups are crucial for irreplaceable data.
Conclusion
In summary, SDXC and exFAT refer to different specifications that are closely tied together when implementing high capacity SD cards:
– SDXC defines cards with capacities from 32GB up to 2TB
– SDXC requires cards meet minimum speed classes for performance
– exFAT file system removes previous volume limits of FAT32
– exFAT enables SDXC cards to store individual files >4GB
– Virtually all high capacity SDXC cards use exFAT
So while not technically the same thing, exFAT file system support is crucial to unlocking the full storage potential of SDXC cards over 32GB. When shopping for a high capacity SD card, checking for both SDXC and exFAT compatibility ensures selecting a properly supported card.
