Choose a Memory Card for 4K Video
By The Flash Centre | Published: 2026-10-20
Category: Buying Guides
Learn how to pick the right SD card for 4K video recording. Compare speed classes, UHS types, and capacities to match your camera and workflow.
Quick answer
For reliable 4K video recording, choose a V30 or higher SD card. V30 handles most 4K modes, while V90 is needed for high bitrate 8K or high frame rate 4K.
Why speed class matters more than capacity
The speed class rating (V30, V60, V90) guarantees a minimum sustained write speed. 4K video, especially at high bitrates, can exceed what a basic Class 10 card delivers, causing dropped frames or recording stops. A V30 card ensures at least 30MB/s write speed, which covers most 4K recording up to 100Mbps. For higher bitrates or 8K, step up to V90.
UHS-I vs UHS-II: compatibility and speed
UHS-I cards are widely compatible and sufficient for most 4K work. UHS-II cards offer faster read/write speeds but require a UHS-II reader or camera slot to unlock their full potential. If your camera supports UHS-II, you can offload footage much faster, but a UHS-I V30 card will still record 4K without issues.
Decision rules for choosing your 4K memory card
- Check your camera's bitrate: Look up the maximum video bitrate your camera records (e.g., 100Mbps, 400Mbps). Divide by 8 to get MB/s. Choose a card with a sustained write speed above that figure. For 100Mbps, a V30 card (30MB/s) is enough. For 400Mbps, you need V90 (90MB/s).
- Match the UHS type to your camera slot: UHS-II cards work in UHS-I slots but run at UHS-I speeds. If your camera has a UHS-II slot, a UHS-II card gives faster transfers. Otherwise, a UHS-I V30 card is sufficient. UHS-I V30 is the safe default; UHS-II V90 is for high-end cameras that support it.
- Choose capacity based on recording time: 4K video at 100Mbps uses about 45GB per hour. A 64GB card holds roughly 1 hour 20 minutes, 128GB holds 2 hours 40 minutes, and 256GB holds nearly 5 hours. For all-day shoots or travel, start with 128GB; for short clips, 64GB is fine.
Product facts at a glance
- Lexar Professional Gold 128GB SDXC UHS-II V90 Memory Card: Read speeds up to 300MB/s and write speeds up to 260MB/s with V90 rating. This card handles the most demanding 4K and 8K video modes without slowdowns, plus fast file transfers to your computer.
Lexar Professional Gold 128GB SDXC UHS-II V90 Memory Card - Delkin Black 64GB SDXC UHS-I V30 U3 Rugged Memory Card: UHS-I V30 card with max write speed of 90MB/s and rugged build. A reliable, affordable choice for standard 4K video recording, especially in tough outdoor conditions where durability matters.
Delkin Black 64GB SDXC UHS-I V30 U3 Rugged Memory Card
Who should buy which card?
Best for
- Videographers recording high-bitrate 4K or 8K footage on UHS-II compatible cameras
- Professionals who need fast offload speeds and maximum reliability
Not for
- Casual vloggers or family video users who only need basic 1080p or low-bitrate 4K
- Users on a tight budget who don't need V90 performance
