Lexar Professional 633x U3 64GB SDXC Memory Card Review

Introduction

The new Lexar Professional 633x SD cards are an update to the 600x SD cards. The cards meet the UHS Speed Class 3 (U3) specification that is given to cards that support 30MB/s or higher continuous write speed, a requirement when recording 4K video.

The Lexar 633x cards are quoted at 95MB/s read and 45MB/s write write speed, essentially the same as the 90MB/s read and 45MB/s write of the 600x cards they replace. The 633x cards are available in 16, 32, 64, 128 and 256GB capacities (the 16GB card has 20MB/s write speed). This review is for the 633x 64GB SDXC card.

Performance

In card reader benchmark tests the 64GB 633x card measured 96.0 MB/s sequential read speed. This is essentailly the same as the Lexar 600x 64GB card that measured 96.6 MB/s. Sequential write speed peaked at 69.3 MB/s, well above the 45MB/s specified by Lexar, but basically the same as the old 600x 64GB card that mesaured 68.6MB/s.

Card: Lexar Professional 633x U3 64GB
Benchmark: CrystalDiskMark 3.0.3 x64
Program settings: 1000 MB, 5 passes, random test data
Operating system: Windows 10 Pro
Motherboard: Gigabyte GA-Z77X-UD3H
Processor: Intel Core i7-3770K @ 4.40GHz
RAM: 32GB DDR3 1600

In digital camera tests the write speed measured 59.1 MB/s in the Canon Rebel T6s. Additional in camera test results will be added to the chart below.

Cameras tested with this card: Canon 5D Mark IV, Canon 5Ds, Canon 80D, Canon Rebel T6i/T6s, Fuji X-Pro2, Fuji X-T10, Nikon D500, Olympus PEN-F, Pentax K-3 II, Sony A7R II, Sony A6300

While the label is new, the actual read and write performance of the 633x card is pretty much the same as the previous 600x cards. The write speed was well above specification, but short of the higher write speeds offered by Lexar's 1000x and 2000x UHS-II cards. The UHS-II cards are backwards compatible with UHS-I cameras and devices but maximum speed is limited to about 95MB/s read and 90MB/s write in UHS-I mode.

Lexar Professional series memory cards have a limited lifetime warranty and are made in Korea.

The following table contains information encoded in the SD card.

Available sizes and prices

Compare prices on the Lexar Professional 633x U3 card. The lowest prices are highlighted in the table below. Prices are updated daily.