Guide note · not an individual product specification
The useful distinction
Understand the requirement.
Identify the full memory-card family and form-factor letter before comparing capacity or performance claims. [C133A]
CFA’s CFexpress 4.0 announcement specifies PCIe Gen4 with NVMe 1.4c and retains the existing card form factors when moving from CFexpress 2.0. Its backward-compatibility and theoretical-throughput statements are not exact-card, camera-mode or file-copy guarantees. [C133B]
Bounded facts, visible unknowns
Specifications and limits
CompactFlash, CFast and CFexpress: choose the card family first facts and limitations
Documented identification
The CompactFlash Association distinguishes PATA CompactFlash, SATA CFast and PCIe/NVMe CFexpress. [C133A]
Important distinction
The CompactFlash Association distinguishes PATA CompactFlash, SATA CFast and PCIe/NVMe CFexpress. [C133A]
Documented distinction
CFA’s CFexpress 4.0 announcement specifies PCIe Gen4 with NVMe 1.4c and retains the existing card form factors when moving from CFexpress 2.0. Its backward-compatibility and theoretical-throughput statements are not exact-card, camera-mode or file-copy guarantees. [C133B]
Verified device list
Not included. Check exact device and accessory documentation.
A boundary, not an omission to guess around.
Record the exact device model and the label beside the port. Obtain its manual and the accessory documentation. Keep unknown properties unknown instead of filling them from a visually similar item.
Before you connect
What to check
Read the full card-family name and Type A / Type B suffix when relevant.
Match camera and reader documentation separately.
Verify capacity and sustained recording requirements without treating bus maxima as achieved performance.
This field note does not approve a connection, publish a pinout or provide a measured template. Use the linked source scope and the checklist as a documentation starting point.
AI-assisted inspection is not independent engineering review. Source scope and access limitations are disclosed below. Procedural checklists are editorial requirements, not hardware measurements.
C133ASource checked · pending review
The CompactFlash Association distinguishes PATA CompactFlash, SATA CFast and PCIe/NVMe CFexpress.
Locator: CFexpress Form Factors; Type A versus Type B; Legacy Standards Access: public page. No copied tables, logos, numeric throughput promises, exhaustive market status or licensed normative specification. Text-only scope.
Claim scope: Identification and explicitly scoped documentation only; not an end-to-end connection approval. Next review due 2027-01-01.
C133BSource checked · pending review
CFA’s CFexpress 4.0 announcement specifies PCIe Gen4 with NVMe 1.4c and retains the existing card form factors when moving from CFexpress 2.0. Its backward-compatibility and theoretical-throughput statements are not exact-card, camera-mode or file-copy guarantees.
Locator: Published 2023-08-28; Performance, Form Factor and Scalability paragraphs. Access: public page. Not a licensed normative specification. No universal exact-device, adapter, throughput or recording-mode qualification.
Computer-generated illustration with prior AI visual review. Not a photograph, measurement or compatibility check. Independent technical and rights review pending.
Assessment 2026-10-22 · earliest scheduled source review 2027-01-01. This is a recorded-date assessment, not a live source check. Page-level independent review is not established by this panel.
CompactFlash Association · Standards-organization domain · inspected 2026-10-03 · due 2027-01-01
Within inspection window
Scoped support: CF uses PATA; CFast uses SATA; CFexpress uses PCIe/NVMe; Type B and XQD share a form factor but camera support is conditional.
Not established / limitations: No copied tables, logos, numeric throughput promises, exhaustive market status or licensed normative specification. Text-only scope.
Locator: CFexpress Form Factors; Type A versus Type B; Legacy Standards
CFA’s CFexpress 4.0 announcement specifies PCIe Gen4 with NVMe 1.4c and retains the existing card form factors when moving from CFexpress 2.0. Its backward-compatibility and theoretical-throughput statements are not exact-card, camera-mode or file-copy guarantees.
Claim scope: 2023-08-28 public announcement; not the normative CFexpress specification.
Recorded evidence only. An inspection date, publisher label, source link or generated packet is not independent technical review, hardware testing, fabrication approval or a compatibility verdict.
