CFexpress

CFexpress is a standard for removable media cards by the CompactFlash Association (CFA). The standard uses the NVM Express protocol over a PCIe interface. 3 different form factors are available, with 1 to 4 PCI-E lanes available.^[1]

CFexpress

CFexpress Type A (left) and Type B (right) cards
Media type	Memory card
Standard	CFexpress standard
Developed by	CompactFlash Association
Dimensions	Type A 20.0×28.0×2.8 mm (0.79×1.10×0.11 in) Type B 38.5×29.8×3.8 mm (1.52×1.17×0.15 in) Type C 54.0×74.0×4.8 mm (2.13×2.91×0.19 in)
Extended from	XQD card
Released	2017

History

On 7 September 2016, the CompactFlash Association announced the CFexpress standard, with specifications based on the PCI Express interface and NVM Express protocol.^[1]

On 18 April 2017 the CompactFlash Association published the CFexpress 1.0 specification.^[2] Version 1.0 will use the XQD form-factor (38.5 mm × 29.8 mm × 3.8 mm) with two PCIe 3.0 lanes for speeds up to 2 GB/s. NVMe 1.2 is used for low-latency access, low overhead and highly parallel access.

On 13 June 2017, Delkin introduced the first CFexpress cards based on the CFexpress 1.0 specification.^[3]

The CFexpress 2.0 standard was announced on 28 February 2019. It features two new card formats - a more compact Type A with one lane, and a larger Type C with four lanes. Existing cards designated as Type B. The NVM Express protocol was upgraded to 1.3.^[4]

The CFexpress 4.0 standard was announced on 28 August 2023. CFexpress 4.0 supports up to four PCIe 4.0 lanes, at 2 GB/s per lane - twice as fast as CFexpress 2.0. The NVM Express protocol was upgraded to 1.4c.^[5]

Comparison

Standard	Version	Launched	Bus	Speed (full-duplex)
CFexpress	1.0	2017 Q2	PCIe 3.0 x2	2.0 GB/s
	2.0	2019 Q1	PCIe 3.0 x1 PCIe 3.0 x2 PCIe 3.0 x4	1.0 GB/s (Type A) 2.0 GB/s (Type B) 4.0 GB/s (Type C)
	4.0	2023 Q3	PCIe 4.0 x1 PCIe 4.0 x2 PCIe 4.0 x4	2.0 GB/s (Type A) 4.0 GB/s (Type B) 8.0 GB/s (Type C)
SD	3.0	2010 Q2	UHS-I	0.1 GB/s
	4.0	2011 Q1	UHS-II	0.3 GB/s
	6.0	2017 Q1	UHS-III	0.6 GB/s
	7.0	2018 Q2	PCIe 3.0 x1	1.0 GB/s
	8.0	2020 Q2	PCIe 4.0 x2	4.0 GB/s
UFS Card	1.0	2016 Q2	UFS 2.0	0.6 GB/s
	2.0	2018 Q4	UFS 3.0	1.2 GB/s
CFast	1.0	2008 Q3	SATA-300	0.3 GB/s
	2.0	2012 Q3	SATA-600	0.6 GB/s
XQD	1.0	2011 Q4	PCIe 2.0 x1	0.5 GB/s
	2.0	2014 Q1	PCIe 2.0 x2	1.0 GB/s

Form factors

CFexpress supports the following card sizes.^[6]

Form Factor	Dimensions (mm)	PCIe Lanes
A	20.0 × 28.0 × 2.8	1
B	38.5 × 29.8 × 3.8	2
C	54.0 × 74.0 × 4.8	4

The larger form factors have more electrical contacts, allowing more PCIe lanes to be used.

Type A is similar in size to an SD card. As of 2023, Sony is the only camera manufacturer that has adopted CFexpress Type A, using it in some of its Sony α cameras. All Sony CFexpress slots also support UHS-II SD cards.^[7]

Type B is the most popular CFexpress form factor, and is used by several camera manufacturers, including Canon, DJI, Nikon, Panasonic, and Red. It has the same size and contacts as an XQD card, allowing a single card slot to accept both XQD and CFexpress Type B cards. Some older cameras with XQD slots have received firmware updates to allow use of a CFexpress Type B card in its XQD slot.^[7]

As of 2023, no devices have implemented CFexpress Type C, and neither cards nor cameras are available.^[7]

• 
  A Sony CFexpress Type A reader and card
• 
  CFexpress Type B (left) next to an SD card (right)
• 
  A CFexpress Type B card with contacts visible
• 
  CFexpress Type B and SD slots on a Nikon Z8 camera

See also

• CompactFlash
• Memory cards
• PCI Express
• NVM Express
• XQD card
• SD Express

Notes