CFexpress vs. SD Bus Interfaces
Comparing 2 standards across 13 specifications. 13 key differences identified.
CFexpress is an ultra-high-speed removable solid-state storage media standard developed by the CompactFlash Association (CFA). Built directly on the PCI Express (PCIe Gen 3/Gen 4) physical bus and NVM Express (NVMe) command set, it is the dominant storage medium for high-end professional digital cinema, mirrorless photography, and broadcast video.
SD Bus Interfaces define the physical and electrical signaling architectures through which SD and microSD cards transfer data with host controllers. Spanning legacy Default/High Speed, Ultra High Speed tiers (UHS-I up to 104 MB/s, UHS-II up to 312 MB/s, UHS-III up to 624 MB/s), and PCIe/NVMe-based SD Express (up to 3,940 MB/s).
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Body
|
CompactFlash Association (CFA) | — |
|
Underlying Storage Architecture
|
PCI Express (PCIe Gen 3 / Gen 4 / Gen 5) + NVM Express (NVMe v1.3/1.4) | — |
|
Type A Dimensions & Bus
|
20.0 × 28.0 × 2.8 mm | 1-lane PCIe (1 GB/s PCIe 3.0 / 2 GB/s PCIe 4.0) | — |
|
Type B Dimensions & Bus
|
38.5 × 29.6 × 3.8 mm | 2-lane PCIe (2 GB/s PCIe 3.0 / 4 GB/s PCIe 4.0) | — |
|
Type C Dimensions & Bus
|
54.0 × 72.0 × 4.4 mm | 4-lane PCIe (4 GB/s PCIe 3.0 / 8 GB/s PCIe 4.0) | — |
|
Type B XQD Compatibility
|
Physically identical exterior shell to Sony XQD (host backward-compatible via firmware) | — |
|
Operating Power Tiers
|
Up to 1.7W (Type A) / Up to 3.0W (Type B) / Up to 6.0W (Type C) | — |
|
Default Speed (DS) / High Speed (HS)
|
— | 12.5 MB/s (25 MHz @ 3.3V) / 25 MB/s (50 MHz @ 3.3V) |
|
UHS-I (SD 3.01)
|
— | SDR12 (12.5 MB/s), SDR25 (25 MB/s), SDR50 (50 MB/s), DDR50 (50 MB/s), SDR104 (104 MB/s @ 208 MHz 1.8V) |
|
UHS-II (SD 4.0)
|
— | 156 MB/s (Full Duplex) / 312 MB/s (Half Duplex) via 2nd pin row LVDS (0.26V) |
|
UHS-III (SD 6.0)
|
— | 312 MB/s (Full Duplex) / 624 MB/s (Full Duplex dual-lane LVDS) |
|
SD Express (SD 7.0 / 8.0)
|
— | 985 MB/s (PCIe 3.0 x1), 1970 MB/s (PCIe 4.0 x1 / 3.0 x2), up to 3940 MB/s (PCIe 4.0 x2) |
|
SD Express Protocol Stack
|
— | PCI Express (PCIe) + NVM Express (NVMe v1.3/1.4) over SD pins |