CFexpress 4.0 announced – Doubles current card speeds up to 8GB/sec
The CompactFlash Association has announced the new CFexpress 4.0 standard. Available in Type A, Type B and Type C varieties, the new specification doubles the speeds compared to the current CFexpress 2.0 specification.
This means that CFexpress Type A cards for Sony shooters now have a theoretical maximum transfer speed of up to 2GB/sec, falling in line with CFexpress 2.0 Type B cards. Type B also doubles, offering a hypothetical 4GB/sec.
CFexpress 4.0 – Feeling the need for speed
CFexpress 4.0 builds on the success of CFexpress 2.0. It employs the industry-standard PCI Express (PCIe) Gen4 bus with an NVM Express (NVMe) 1.4c interface. Like CFexpress 2.0, the new 4.0 specification comes in the same three different form factors.
CFexpress Type A – currently only used by Sony cameras – doubles the maximum speed limit from 1GB/sec up to 2GB/sec. Likewise, CFexpress Type B, which is currently being used by pretty much everyone except Sony (Nikon, Canon, etc.), also doubles its speed limit. This goes from 2GB/sec to a 4GB/sec theoretical maximum.
CFexpress Type C doesn’t actually appear to be in use anywhere in the world of photo and video yet. But, it doubles its maximum speed from 4GB/sec to 8Gb/sec.
Don’t expect camera speed improvements yet
Although each of the hypothetical card speeds double for their respective form factors, we may not see any massive changes in our cameras for the foreseeable future. Yes, faster cards mean we can potentially get higher bitrate video with further increased resolution and colour depth information.
They also mean that for sports and wildlife shooters, you’re able to shoot faster for longer. Your buffer can- again, hypothetically – be written out to the memory cards in half the time. But that doesn’t necessarily mean that camera manufacturers will take advantage of this extra speed.
After all, Sony’s CFexpress Type A cards are half the speed of the Type B cards used in other cameras. The Sony A1 (buy here) and Sony A7R V (buy here) still put out 8K video, though. Just like cameras using Type B. And many Type B cameras don’t currently utilise anywhere near card maximums.
The extra speed increase, however, does mean that memory cards are potentially going to get even larger than they are now, breaking that 1TB barrier. It also means that for those shooting a lot of content, even though the camera might not need it, you’ll be able to back it up to your computer much more quickly than in the past.
You’ll probably need USB 4 or Thunderbolt 3
This is another reason not to get too excited just yet. To utilise the speeds of CFexpress 4.0 Type B cards, you’ll need USB 4 or Thunderbolt 3 ports on your computer. USB 3.2 Gen 2 is commonplace these days, but it’s limited to 10Gbps (1.25GB/sec). This is below all CFexpress 4.0 card speed specifications.
There is USB 3.2 Gen 2×2, which doubles the speed limit to 20Gbps (2.5GBsec), but it’s not very commonly available. This is why most CFexpress Type B card readers utilise Thunderbolt 3, with its higher 40Gbps (5GB/sec) speed limit. Such readers may be compatible with USB 3.2, but throttled on speeds.
For CFexpress 2.0 Type A, USB 3.2 Gen 2 can utilise the maximum speed of the card. With CFexpress 4.0 Type A, you’ll need to step up to USB 3.2 Gen 2×2 or Thunderbolt to make full use of the card. And for CFexpress 4.0 Type B, you’ll need at least USB 4 or Thunderbolt 4 at 40Gbps (5GB/sec). If CFexpress 4.0 Type C ever becomes a real thing, you’ll need USB 4 v2.0 to plug in a reader.
CFexpress 4.0 is Backwards compatible
Although you may need to upgrade your computer (or at least its USB sockets) to take full advantage of the new speeds, you can still use the cards in your existing readers. The CompactFlash Association says that the cards are backwards compatible with CFexpress 2.0 compatible devices.
So, while you may be able to get faster cards, at this point, they don’t really offer much of an advantage over CFexpress 2.0 cards for most people. It’s a bit like buying UHS-II V90 SD cards when all of your cameras and card readers only support UHS-I. Sure, it’ll work, but it’s a waste of money over just buying a UHS-I card.
CFexpress Type 4.0 will probably feel the same way for a little while. Spending way more money than you need to while getting no advantage over CFexpress 2.0. But once cameras, devices and computers can all keep up with the new card speeds, we will definitely start to see the benefits.
And, of course, prices will come down, the same way they have with CFexpress 2.0, which is now cheaper than those V90 SD cards I mentioned above.
You can read the full announcement on the CompactFlash Association website.
According to Wikipedia, and updated to current specs, CFexpress is a standard for removable media cards proposed by the CompactFlash Association (CFA). The standard uses the NVM Express protocol over a PCIe 4.0 interface with 1 to 4 lanes where 2 GB/s data can be provided per lane.
As with many things in life, it depends. Some older SD cards offer better prices for non-speed-critical uses. Generally, they are more compatible with most modern cameras. CFexpress, on the other hand, is more robust, durable, and typically faster at the high end.
While both SD cards and CFexpress cards are small, fast storage devices for cameras, they are not the same thing. SD cards have a different form factor to CFexpress, and they are not interchangeable. You should pick the card type depending on your camera and needed performance.
John Aldred is a photographer with over 20 years of experience in the portrait and commercial worlds. He is based in Scotland and has been an early adopter – and occasional beta tester – of almost every digital imaging technology in that time. As well as his creative visual work, John uses 3D printing, electronics and programming to create his own photography and filmmaking tools and consults for a number of brands across the industry.