
Lexar High-Performance 633x 256GB
Score: 60/100
Lexar E-Series 256GB
Score: 81/100Rankings

Lexar's 256 GB E-Series microSDXC provides up to 100 MB/s read and 140 MB/s write speeds, IPX7 waterproofing and a broad compatibility range across smartphones, tablets and action cameras. However, its UHS-I performance cannot exploit the higher speeds of UHS-II devices, and some variants lack detailed temperature specs. It's a solid choice for mobile and action-camera users seeking rugged storage.

Lexar's 256 GB 633x microSDXC offers up to 100 MB/s read speed, a V30 rating, and includes a micro-SD to SD adapter for versatile use. Its slower 45 MB/s write speed and lack of waterproofing limit high-end video applications. Suitable for smartphones, tablets and action cameras where large capacity and broad compatibility are priorities.
| Attribute | ![]() | ![]() |
|---|---|---|
256 GBbest | 256 GBbest | |
100 MB/sbest | 100 MB/sbest | |
45 MB/s | 140 MB/sbest | |
| ↓ lower better | 453.6 g | 0.2 gbest |
— | 10 yearsbest | |
| ↓ lower better | 1.02 mmbest | 1.02 mmbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Performance(2) | ||
Write Speed (MB/s) | 45 MB/s | 140 MB/s |
UHS Speed Class | U3 | UHS-I |
Design(1) | ||
Weight (g) | 453.6 g | 0.20 g |
General(1) | ||
Compatibility | wide compatibility with any UHS‑I device while remaining backward compatible with Class 10, V10 and U1 standards | Smartphones, tablets, drones, action cameras, GoPro, Nintendo Switch |

Products in the top-left offer the best value (high score, low price).

Professional testing shows the Lexar 633x card delivers real-world read speeds near 97 MB/s and write speeds around 69 MB/s, surpassing its advertised specifications and confirming its suitability for 4K video capture. Reviewers acknowledge its solid mid-range performance but point out that newer Lexar BLUE models provide higher peak speeds, making the 633x less compelling for users seeking top-tier throughput.
Everyday users praise the large 256 GB capacity, the included SD adapter for easy file transfer, and the peace of mind from the lifetime warranty. They also highlight the card's reliable 4K video performance and compatibility with a wide range of devices. However, some users note the write speed feels modest compared to newer offerings, and the lack of UHS-II support limits its appeal for high-end professional use.




Professional reviewers note that Lexar's high-end GOLD card provides the fastest UHS-II speeds suitable for demanding 4K/8K workflows, while the SILVER PLUS and PLAY cards offer solid V30 performance and rugged durability for action cameras and gaming consoles. The inclusion of an SD adapter and a lifetime warranty are repeatedly praised, though reviewers caution that UHS-II benefits require compatible host devices.
Everyday users provide limited feedback, but the few available comments praise the fast transfer rates and reliability for gaming and video storage. Some users express uncertainty due to the lack of detailed performance data, especially for the GOLD and PLAY variants.