Lexar 633x 512GB microSDXC Memory Card

633x — 100MB/s Read

Fast Transfer for Large Files

The 633x speed rating is Lexar’s legacy designation for memory card performance, derived from the original CD-ROM speed unit where 1x = 150KB/s. At 633x, the card achieves 633 × 150KB/s = approximately 95–100MB/s sequential read throughput on a compatible reader. This read speed primarily affects two things: how quickly files can be transferred from the card to a computer when reviewing or backing up footage, and how quickly the device can access previously stored content for playback. At 100MB/s, a 10GB 4K video file transfers in approximately 100 seconds via a UHS-I card reader — roughly double the time of a 200MB/s UHS-II card but significantly faster than older 80–90MB/s UHS-I cards. The 70MB/s write speed determines how quickly data from the camera sensor can be saved to the card, which governs burst depth (how many RAW photos can be taken in rapid succession before the buffer fills) and whether the card can keep pace with high-bitrate video streams. At 70MB/s, the card handles bitrates up to approximately 560Mbps — well above the maximum bitrates produced by any consumer smartphone or action camera.

U3 · V30 · A2

4K Recording · App Storage · Guaranteed Minimums

Speed class ratings communicate guaranteed minimum performance floors. U3 guarantees a minimum sustained write speed of 30MB/s — sufficient for 4K UHD recording at the bitrates used by current smartphones, action cameras, drones and handheld gaming devices. V30 is the Video Speed Class equivalent of U3, used by newer device firmware to verify card compatibility for 4K recording. Devices that state they require a V30 card will accept this card. The A2 app performance class guarantees random read IOPS of 4,000 and random write IOPS of 2,000 — the higher-tier spec for running Android applications from external storage. On compatible Android devices that support adoptable storage or app-to-SD card features, an A2-rated card provides noticeably more responsive app loading than an A1 card. All three ratings apply to this 512GB card — the same guarantees hold at this capacity as at smaller sizes in the range. Lexar validates these ratings through testing in their quality labs across a broad range of compatible devices.

512GB Capacity

Hours of 4K · Thousands of Photos · Large Libraries

512GB is the largest capacity in the Lexar 633x microSDXC range. At typical 4K UHD recording bitrates from a smartphone or action camera (30–80Mbps at 30fps), 512GB holds approximately 17–42 hours of continuous video — sufficient for extended travel documentation, event coverage across multiple days or complete content library storage without swapping cards. For photography, 512GB holds approximately 130,000 compressed JPEG photos at 4MP quality or approximately 7,000 uncompressed RAW files from a high-resolution camera. For Nintendo Switch or tablet gaming, 512GB provides the equivalent of the internal storage of multiple high-specification gaming consoles and holds large game libraries. The 512GB capacity makes the card particularly suitable for users who prefer not to manage storage frequently — one card that holds a full trip’s content rather than multiple smaller cards requiring mid-shoot management. The included SD adapter allows the same card to be used in a standard SD camera, laptop slot or USB card reader for file management.

Great choice if you…

✔ Need a large-capacity microSD for a smartphone, tablet, action camera or drone
✔ Record 4K video and want U3/V30 performance without dropped frames
✔ Want A2 app performance for running Android apps from the card
✔ Travel and want enough storage for an entire trip without changing cards
✔ Want an SD adapter included for direct use in cameras and laptops

Consider something else if…

✖ You record high-bitrate Cinema 4K or 8K requiring V60 or V90 — see Lexar Professional 1667x UHS-II
✖ You use the card in a dashcam or CCTV camera — see SanDisk High Endurance for continuous overwrite
✖ You need maximum read speed for professional burst photography — see Lexar Professional 1066x or 1667x

Technical Specifications

Box Contents

Condition

Brand New — Retail Packaging

Warranty

Limited Lifetime (Lexar)

Delivery

4–5 Working Days · Fully Tracked