Buying guide
Memory Cards Buying Guide (2027)
How to choose a memory card in 2027: formats, buses, V30 V60 V90 classes, CFexpress explained, capacities and avoiding counterfeits.
Formats and buses: fit first, speed second
Your camera dictates format: SD (UHS-I or UHS-II bus), microSD, CFexpress Type A or Type B, or legacy XQD and CFast in older cinema bodies - none are interchangeable without the exact slot. UHS-II SD cards add a second pin row and only deliver their speed in UHS-II slots and readers. CFexpress Type B is the flagship standard for 8K and extreme bursts. Confirm format and bus in your manual before comparing a single speed figure.
Read the guaranteed classes, not the box peaks
Video speed class is a contract: V30 guarantees 30 MB/s sustained writes, V60 guarantees 60, V90 guarantees 90. U3 and Class 10 are older floors of 30 and 10 MB/s. The big MB/s number on the box is a peak read under ideal lab conditions with a specific reader. Match the V class to your highest-bitrate recording mode as listed in your camera manual, then compare reads for offload convenience.
Capacity strategy and card rotation
Two 256GB cards beat one 512GB card for risk: mirrored dual-slot recording, per-segment swaps at weddings and events, and a smaller loss if a card dies or vanishes. Video shooters should size capacity to the day at their codec's data rate - 8K RAW can consume over 100 GB per hour - and everyone should offload, verify two backups, and only then format in-camera.
Counterfeits, care and readers
Buy best-selling cards only from authorised sellers; counterfeits with faked capacity cause the majority of catastrophic card stories and are rampant in third-party marketplace listings. Test new cards with a full-write verification tool before paid work. Keep cards in a labelled case, format in the shooting camera, and close the speed chain with a reader and cable that match your card's bus - the reader is half the offload spec.
Start with our top 3
The three highest-ranked products in our full memory cards ranking. Read the in-depth review where one exists, or jump to the product in the ranked list.
SanDisk Extreme Pro SDXC UHS-I 128GB
The UHS-I benchmark: 200 MB/s reads and V30 reliability for everyday shooting.
- Format / bus: SDXC, UHS-I
- Speed class: V30, U3, Class 10
Lexar Professional 2000x SDXC UHS-II
UHS-II speed up to 300 MB/s reads for fast offloads and cleared buffers.
- Format / bus: SDXC, UHS-II
- Speed class: U3, V60 or V90 depending on capacity, check SKU
ProGrade Digital SDXC UHS-II V90 Cobalt
A true V90 card with 300 MB/s reads built for professional video and bursts.
- Format / bus: SDXC, UHS-II
- Speed class: V90, U3, Class 10
Questions, answered
What card does my camera actually need?
Your manual's recording-mode table lists the required speed class per codec and frame rate. Buy one class above your most demanding regular mode for thermal and ageing headroom.
Are expensive cards more reliable, or just faster?
Both, generally: pro lines add better controllers, serialisation, health tools and support. The reliability jump from no-name to any reputable brand dwarfs the jump between reputable brands.
How do I spot a counterfeit card?
Price far below authorised retail, misspelled packaging, and capacity that fails a full-write test. Verify with tools like H2testw or F3, register serialised cards, and return anything suspicious immediately.
Do memory cards wear out?
Flash memory has finite write cycles, but camera cards typically retire from capacity needs or physical loss first. Health monitoring on pro lines gives early warning; replace any card that errors even once on a job.