SD Express is an SD memory card standard that adds PCIe and NVMe interfaces alongside the traditional SD interface. A compatible device can use the PCIe/NVMe connection for much higher bus bandwidth; an older device that supports only the traditional interface can use the card through that interface, but cannot access SD Express performance.
What makes SD Express different?
A regular SD card generally communicates over a traditional SD bus, such as UHS-I, UHS-II, or UHS-III. SD Express adds a second interface path: PCIe, the bus, paired with NVMe, the storage protocol. With a host that supports SD Express, the card can be accessed as NVMe storage. The SD Association describes this design as adding PCIe and NVMe alongside the legacy SD interface: SD Express implementation overview.
That added interface—not simply a faster speed label—is the key difference. The card retains its traditional SD interface, so it may still work in an older compatible slot, but its PCIe/NVMe path requires a host that implements the relevant SD Express support.
How fast is SD Express?
The SD Association lists the following maximum bus-interface speeds for SD Express configurations. These are interface ceilings, not guaranteed card read or write speeds:
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- Nintendo Switch 2 uses a new standard of expandable memory card called microSD Express (sold separately). This kind of memory card is needed for faster access speeds and to ensure games will run smoothly.
- Please note: Nintendo Switch 2 is only compatible with microSD Express cards. If the microSD cards you have used for Nintendo Switch do not support microSD Express standards, you cannot use them with Nintendo Switch 2.
| Configuration | Maximum bus speed | Specification tier |
|---|---|---|
| PCIe Gen.3 x1 | Up to 985 MB/s | SD7.0/SD7.1 |
| PCIe Gen.4 x1 or PCIe Gen.3 x2 | Up to 1970 MB/s | SD8.0 |
| PCIe Gen.4 x2 | Up to 3940 MB/s | SD8.0 full-size SD configuration |
| PCIe Gen.4 x1 | Configuration listed for SD8.0 microSD | SD8.0 microSD configuration |
The SD Association cautions that maximum bus speed differs from card performance. Actual transfer rates depend on the card, host, and task. In particular, 3940 MB/s is not a typical or guaranteed speed for every SD Express card. See the Association’s SD bus-speed overview.
What do SD Express speed-class labels mean?
SD Express cards can carry speed-class markings such as E150, E300, E450, and E600. These classes describe defined minimum access-performance levels under specified conditions; they are not the same as the maximum bus-speed figures above. When comparing cards, use the card’s stated performance specifications and class rather than treating the interface ceiling as its guaranteed transfer rate. The SD Association explains the classes in its SD Express Speed Class document for the SD 9.1 specification.
Rank #2
- NEXT GEN GAMING: Works with Nintendo Switch 2.
- READY FOR TOMORROW. Ready for future products with a PCIe-NVMe interface; performs at UHS-I speeds with microSD UHS-I and UHS-II devices.
- EXPONENTIALLY FASTER PERFORMANCE. Up to 4.4 times faster transfer speeds than our fastest microSD UHS-I cards [9]. Transfer a 2-hour HD movie in less than 3.5 seconds [1]; save up to 2.8 minutes transferring 60 minutes of 4K UHD video [4] shot at 30 fps when paired with the SanDisk PRO-READER SD Express Dual Card (sold separately) [9]
- DURABILITY YOU CAN COUNT ON: Cards are waterproof, temperature-proof, humidity-proof, drop-proof, shock-proof, magnetic-proof, x-ray proof, and wear-out proof [5].
- HEAT MANAGEMENT REIMAGINED. SanDisk ThermAdapt helps keep devices from overheating with a specially designed enclosure and controller that uses dynamic adaptive thermal management.
Will an SD Express card work in an older slot?
It can, if the older device supports the card’s traditional SD interface and form factor. In that case, the card operates over the legacy interface, so performance is limited by that interface. Backward compatibility does not turn the older slot into an SD Express host; PCIe/NVMe operation requires explicit support in the device or reader. Do not assume a reader exposes the faster path merely because an SD Express card fits.
Before buying, verify both the card’s form factor—full-size SD or microSD—and the device documentation for SD Express support. The SD Association’s FAQ and speed-class overview provide additional standard information.
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- TRANSFER SPEEDS UP TO 800 MB/S: With sequential read speeds up to 800 MB/s, get into your game up to 4× faster than our standard microSD cards (UHS I)¹.
- DYNAMIC THERMAL GUARD: Keeps its cool even when the action heats up. Dynamic Thermal Guard helps reduce overheating for fast, smooth gameplay.
- ALL YOUR GAMES ON ONE TINY CARD: Store all your games and downloadable content (DLCs) with up to 512GB of reliable storage. No deleting. No compromises.
- 6-PROOF PROTECTION WITH 3-YEAR LIMITED WARRANTY: Built to last, made for peace of mind. Anything can happen when you’re gaming on the go. With 6 types of protection²⁻⁹, the P9 Express can handle it all—helping maintain your game progress.
- NEXT-GEN AND BACKWARD COMPATIBLE: Your microSD Express card is compatible with Nintendo Switch 2¹⁰ and microSD UHS-I¹¹ devices, including tablets, drones, cameras and more.
Which SD Express generation and form factor do you need?
- SD7.0: Introduced SD Express for full-size SD cards with PCIe Gen.3 x1.
- SD7.1: Extended SD Express to the microSD form factor.
- SD8.0: Added PCIe Gen.4 and two-lane configurations. The SD Association lists PCIe Gen.4 x2 for full-size SD and PCIe Gen.4 x1 for the SD8.0 microSD configuration.
“SD Express” by itself therefore does not identify a single speed tier. Check the card’s generation and interface configuration against what the host supports. The SD Association’s SD Cards with PCIe-NVMe Interfaces white paper discusses the interface, while its SD Express Speed Class document covers the later class labels.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Who benefits from SD Express?
SD Express may be useful when both the device and workload can take advantage of its faster interface. The SD Association identifies high-resolution video capture and playback, RAW burst photography, 360-degree video, mobile computing, gaming, IoT, and automotive storage as potential applications. Its implementation material also discusses running applications or an operating system directly from a card as a possibility enabled by faster sequential and random access. These use cases do not mean that every camera, computer, or game device supports SD Express.
Quick Recap
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- The perfect card for the Nintendo Switch 2 delivers revolutionary performance that is 4x faster than typical UHS-I microSD cards
- PCIe technology delivers read speeds up to 900MB/s so the game loads faster
- Write speed up to 600MB/s deliver accelerated download speeds when paired with the Lexar microSD Express card reader
- Level-up your handheld gaming experience with next-gen tech
- 1TB microSD Express card offers more space for your favorite games
Rank #4
- NEXT GEN GAMING: Works with Nintendo Switch 2.
- READY FOR TOMORROW. Ready for future products with a PCIe-NVMe interface; performs at UHS-I speeds with microSD UHS-I and UHS-II devices.
- EXPONENTIALLY FASTER PERFORMANCE. Up to 4.4 times faster transfer speeds than our fastest microSD UHS-I cards [9]. Transfer a 2-hour HD movie in less than 3.5 seconds [1]; save up to 2.8 minutes transferring 60 minutes of 4K UHD video [4] shot at 30 fps when paired with the SanDisk PRO-READER SD Express Dual Card (sold separately) [9]
- DURABILITY YOU CAN COUNT ON: Cards are waterproof, temperature-proof, humidity-proof, drop-proof, shock-proof, magnetic-proof, x-ray proof, and wear-out proof [5].
- HEAT MANAGEMENT REIMAGINED. SanDisk ThermAdapt helps keep devices from overheating with a specially designed enclosure and controller that uses dynamic adaptive thermal management.
How to choose between SD Express and a regular card
- Check the host: Look up the exact device or reader specifications. Confirm explicit support for SD Express, not just an SD or microSD slot.
- Match the form factor: Choose full-size SD or microSD as required by the device.
- Match the interface configuration: Confirm that the host supports the card’s SD Express generation and PCIe lane configuration.
- Compare card performance: Use the card’s stated read/write specifications and speed class. Do not substitute the interface’s maximum bus speed for actual card performance.
- Consider the workload: SD Express is worth considering when the compatible device and task benefit from faster removable storage. Otherwise, a regular card suited to the device may be the more sensible choice.
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