Why All These Flash Drive Form Factors?

Changes in power, performance, and chips have forced new flash memory form factors.

William G. Wong

Sebastien Jean

Related To:

Electronic Design

March 31, 2026

What you'll learn:

How disk drives and SSDs have changed over time.
Why are there all of these different SSD form factors?
What is ESDFF E1 and E3?

M.2 and EDSFF E1 and E3 form factors are typically used in enterprise server environments.

Enterprise and Data Center Standard Form Factors (EDSFF) include E1 and E3, which have supplanted the conventional M.2 and 2.5-in. form factors like U.2 in high-end servers. M.2 slots are often found on motherboards. However, server removable drives, now dominated by EDSFF, support the latest PCI Express-based NVMe interfaces that provide massive throughput.

I talked with Sebastien Jean, Chief Technology Officer at Phison Electronics, about the history and evolution of drive form factors and how flash memory has changed the form-factor design. We talk about how and why the EDSFF form factors evolved and how higher density is forcing changes in cooling technology in these servers.

About the Author

William G. Wong

Senior Content Director - Electronic Design and Microwaves & RF

I am Editor of Electronic Design focusing on embedded, software, and systems. As Senior Content Director, I also manage Microwaves & RF and I work with a great team of editors to provide engineers, programmers, developers and technical managers with interesting and useful articles and videos on a regular basis. Check out our free newsletters to see the latest content.

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Check out my blog, AltEmbedded on Electronic Design, as well as his latest articles on this site that are listed below.

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I earned a Bachelor of Electrical Engineering at the Georgia Institute of Technology and a Masters in Computer Science from Rutgers University. I still do a bit of programming using everything from C and C++ to Rust and Ada/SPARK. I do a bit of PHP programming for Drupal websites. I have posted a few Drupal modules.

I still get a hand on software and electronic hardware. Some of this can be found on our Kit Close-Up video series. You can also see me on many of our TechXchange Talk videos. I am interested in a range of projects from robotics to artificial intelligence.

Sebastien Jean

Chief Technology Officer, Phison Electronics

Sebastien Jean is the Chief Technology Officer at Phison US, where he focuses on developing technology strategy and building alliances with other innovative companies. Before joining Phison, he held senior technology positions at Micron, SanDisk, and Western Digital.

At Phison, he helped devise an iterative technology roadmap that advances Security, AI, PCIe Gen 5, USB4, BGA NVMe, Client Gaming Drive, and Enterprise High-density E1.S. He earned a BS in Computer Science at the University of Ottawa (Canada).