E1.S Form Factor

Overview

E1.S is the dense, high-performance EDSFF compute-storage form factor, projected to exceed 40% of SSD unit volume by 2029 and often paired with liquid cooling. It is positioned as complementary to the high-capacity E2 form factor: E1.S serves high-density and compute use cases while E2 serves high capacity, giving the industry a pair to design with. E1.S — specifically the E1.S 9.5 variant — is the center of the EDSFF liquid-cooling effort: after a September 2025 OCP call, three converging proposals for how to do liquid cooling on E1 were consolidated into a single in-progress draft spec.