The CFexpress storage format is set to get even faster thanks to the latest CFexpress 4.0 standard announced by the CompactFlash Association (CFA) trade organization earlier this week. The current CFexpress 2.0 standard is used in several high-end cameras, such as the Sony a1 and Nikon Z9.

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CFexpress 2.0 already has a stellar reputation for extremely fast performance, with maximum transfer speeds hitting up to 1 GB/s (1000MB/s) and 2 GB/s (2000MB/s) for Type A and Type B cards, respectively. However, keep in mind that's 'theoretical max speed.' Even the current fastest CFexpress cards on the market don't achieve this maximum speed, although they are coming close. The just-announced CFexpress 4.0 standard aims to double the performance, with a theoretical maximum throughput of 2 GB/s for Type A and 4 GB/s for Type B.

The underlying technical advancements are two-fold. CFexpress 4.0 upgrades to the faster PCI Express (PCIe) Gen4 standard (hence the jump from 2.0 to 4.0 in the naming scheme) along with the NVM Express (NVMe) 1.4c logical interface, whereas CFexpress 2.0 currently uses PCIe Gen3 and NVMe 1.3c.

'While the theoretical maximum speed of PCIe 4.0 is twice as fast as PCIe 3.0, that doesn't mean that a PCIe 4.0 drive or memory card will be twice as fast as a PCIe 3.0 one,' said Tom Brant, Deputy Managing Editor of 'A lot depends on the number of PCIe lanes involved and the specifications of the drive interface.'

Indeed, the newer PCIe Gen4 standard allows for faster data throughput per lane, and as before with CFexpress 2.0, there are three different form factors, or card types, each with a different number of PCIe bus lanes. CFexpress 4.0 Type A is the smallest of the three and is the card type we see readily adopted already by Sony for cameras such as the Sony a7S III and Sony a7 IV. The Type A cards feature a PCIe interface with just a single lane, and with CFexpress 4.0, a Type A card has a maximum theoretical performance of up to 2 GB/s.

The Type B form factor, which we've seen in several Canon and Nikon cameras, offers even faster maximum theoretical performance. The new CFexpress 4.0 Type B cards feature a PCIe Gen4 interface with two lanes and a max theoretical throughput of 4 GB/s.

A third form factor, Type C, offers a four-lane PCIe Gen4 interface and up to 8 GB/s of maximum data transfer performance. However, this largest card has yet to see widespread adoption in cameras.

The CFexpress 4.0 Logical and Physical Specifications

Beyond the speed improvements, the CFA highlights power efficiency as another key aspect of the new standard. Despite the increased performance of this new storage format, CFexpress 4.0 is designed to maintain certain power consumption targets to help improve the adoption of CFexpress 4.0, especially among battery-powered cameras and other devices. The new standard allows for 2500 mA power draw from the smallest Type A cards, 3000 mA from Type B, and 3500 mA from large Type C cards.

CFexpress 2.0 cards, like those from ProGrade Digital, for example, list a normal operating current of 1500 mA, up to a max of 2500 mA, for its 'Gold' and 'Cobalt' series of Type B cards. As such, it seems likely that the faster-performing CFexpress 4.0 cards could draw more power than CFexpress 2.0 cards of similar card types.

Don't toss out your old memory cards

Although we don't yet know when we'll begin to see cameras shipping with CFexpress 4.0 support, the Panasonic S1 and S1R debuted with support in 2019, right around the time CFexpress 2.0 was first announced. So perhaps CFexpress 4.0-compatible cameras are right around the corner?

What we do know at this point, is that those who have already invested in expensive CFexpress 2.0 cameras and cards (although prices are perhaps coming down somewhat) aren't going to have to start over with new cards right away. If you've purchased a handful of pricey CFexpress 2.0 cards, you'll be pleased to know that the upcoming CFexpress 4.0 standard retains compatibility with 2.0 cards. So, you'll still be able to use your CFexpress 2.0 cards in a future camera that utilizes the CFexpress 4.0 standard – of the same card type of course.