What's faster than a Nikon Z9? Delkin's latest CFexpress cards, of course!

Graphic depicting a Nikon Z9 racing a CFexpress card on a drag strip
(Image credit: Future)

It's been mere weeks since Lexar announced it's launching the world's fastest CFexpress Type B and Type A cards. But not to be outdone, arch rival Delkin Devices has some impressive speed claims for its newly updated Black series CFexpress Type B cards. Where Lexar was making headlines with outright speed claims, Delkin is promoting the minimum sustained write speed of the latest Black-series cards - arguably a more relevant performance metric in real-world use.

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(Image credit: Delkin Devices)

Delkin claims the Black cards can write data faster than Nikon Z9's own image buffer. Ordinarily, the camera buffer would fill up once 79 images have been shot, leading to a slow-down in burst shooting as the memory card becomes a data writing bottleneck. Not so with the new Delkin Black cards (supposedly), as Delkin claims that a Black card can write lossless Raw photos without ever hitting the Z9's 79-shot buffer, and will only stop once the card is full. For a 325GB card, that equates to 6,661 photos, each being 55.1MB in files size, recorded without interruption. Impressive stuff.

The Nikon Z9s card slots. The 'Caution: Hot' warning could be particularly appropriate! (Image credit: James Artaius)

According to Delkin, “The camera buffer never completely filled during testing, resulting in no stops or lagging”. When it comes to video write speed, Delkin claims that a Z9 loaded with a new Black-series card can record 10 minutes of 8K RAW 12-bit 6:1 compression footage (7,680 x 4,320) at 60 frames per second.

(Image credit: Delkin Devices)

All this translates to a minimum sustained write speed of 1530MB/s, far exceeding the VPG400 (Video Performance Guarantee) 400MB/s Compact Flash Association rating given to some rival CFexpress cards, and making them the fastest cards by this measure. For context, ProGrade Digital's top-of-the-range CFexpress Type B 1700 Cobalt Memory Card has a minimum sustained write speed of 1400MB/s, while Angelbird's AV PRO CFexpress MK2 Type B card can 'only' deliver 1300MB/s sustained.

The previous speed king for sustained write speed: ProGrade's Cobalt CFexpress Type B card (Image credit: Angela Nicholson/Digital Camera World)

Capacities of the new Black-series cards include 75GB, 150GB, 325GB, 512GB and 650GB versions, though the 75GB version is only rated for 1240MB/s minimum sustained write speed.

Expect to pay $130 for the 75GB card, while the 150GB, 325GB, 512GB and 650GB versions will cost $175, $425, $500 and $725 respectively.

Just be careful to choose newest generation of Black cards, as older, slightly slower, Black-series CFexpress Type B cards are still being sold alongside the newer versions.

Delkin's new Black-series CFexpress Type B cards are available to buy now from B&H

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Ben Andrews

Ben is the Imaging Labs manager, responsible for all the testing on Digital Camera World and across the entire photography portfolio at Future. Whether he's in the lab testing the sharpness of new lenses, the resolution of the latest image sensors, the zoom range of monster bridge cameras or even the latest camera phones, Ben is our go-to guy for technical insight. He's also the team's man-at-arms when it comes to camera bags, filters, memory cards, and all manner of camera accessories – his lab is a bit like the Batcave of photography! With years of experience trialling and testing kit, he's a human encyclopedia of benchmarks when it comes to recommending the best buys.