ProGrade Digital Cobalt CFexpress Type B

£316-£537 / $430-$774 https://progradedigital.com

ProGrade Digital was launched in February 2018, so it’s a newcomer to the memory card market, but its founders have a background in older memory brands and it has quickly gained recognition. Nikon even used ProGrade’s Cobalt CFexpress cards to obtain the quoted burst depth figures for the Z 9.

ProGrade Digital makes two lines of CFexpress Type B card, the Gold series, which have read speeds of up to 1700MB/s and write speed of up to 400MB/s, and the Cobalt cards, which have an NVMe PCIe 3.0 x4 interface, helping them to deliver a similar max read speed to the Gold card, but much faster write speeds of 1500MB/s. These speeds make the Cobalt cards suitable for recording 8K footage or high bit rate and raw video.

The Cobalt CFexpress cards are available in two capacities, 325GB and 650GB, which means the starting price is high (£316/$430).

Testing revealed a read speed of around 858MB/s and a write speed of about 900MB/s, which is impressive but below the stated maximum. For the next test, we dragged our folder of 200 images from the card onto the computer. It took 25 seconds for the files to copy across – the fastest time we’ve experienced.

Next, we put the card in the Nikon Z 7II to check the burst speed and depth in Continuous High (extended) shooting mode. When shooting Fine-quality JPEGs, we were able to capture up to 130 images in one go, beating the claimed max burst of 113 images. However, when shooting uncompressed 14-bit raws we were only able to capture 44 in one burst, four short of the claimed max.

While the bench test figures don’t match the max data transfer speed printed on the box, the ProGrade Digital Cobalt CFexpress Type B proved itself to be a solid performer, enabling high JPEG burst depths, coping with 4K 60p video recording and transferring images quickly.

PROS Up to 650GB capacity; solid performance

CONS Only available in two capacities; high price