Lexar’s parent company, Longsys, has officially released its Diamond Series CFexpress Type B cards. The series was announced in April as the fastest in the world and promises transfer speeds of up to 1,900 MB/s.

The new memory cards appear to be very impressive. Lexar claims that the new Diamond series CFexpress memory cards will have write speeds of up to 1,900 MB/s and read speeds of up to 1,700 MB/s, with sustained write performance of up to 1,600 MB/s — easily enough to qualify for the Compact Flash Association’s VPG 400 certification, which this series carries. Those figures are significantly higher than competitors, but advertised speeds do not always correspond to actual performance.

PetaPixel tested the new Lexar Diamond Series CFexpress Type B cards in real-world scenarios to see how they compare to other CFexpress cards on the market.

The cards averaged peak write and read speeds of 833MB/s and 794.5MB/s, respectively, in PetaPixel’s testing. While this is far from the claimed peak speeds, it is faster than every other CFexpress Type B card PetaPixel has tested, except for Sony’s Tough CFexpress Type B cards.

Lexar’s Diamond Series fell short in sustained performance, measuring around 500MB/s, PetaPixel noticed a significant performance increase over its competitors in burst photo performance. The Lexar Diamond card, according to PetaPixel, was able to write images taken on a Canon R5’s highest burst photo speed for ‘just over 30 seconds,’ which is a significant improvement over the second-place finisher, the Delkin Devices Black Series cards, which topped out just shy of 20 seconds before hitting the buffer.

Lexar Diamond Series CFexpress Type B memory cards are priced at $220 and $380 for 128GB and 256GB capacities, respectively.

More info on Lexar’s website.