800V DC Sidecar Architecture

Overview

The 800V DC Sidecar Architecture is a data center power distribution approach that centralizes AC-to-DC power conversion in a dedicated "sidecar" rack, distributing high-voltage DC (+/-400V, totaling 800V) to adjacent IT racks. This architecture replaces per-rack PSUs with centralized conversion, dramatically reducing copper usage (by up to 82% versus traditional AC busway), improving efficiency, and simplifying rack design.

The architecture is gaining rapid adoption as AI rack densities exceed 100 kW, with OCP's Mount Diablo specification and Diablo 400 project defining open standards. Multiple vendors including Megmeet, Liteon, Rittal, and Eaton have developed production 800V sidecar systems, with NVIDIA actively driving the architecture. The shift is closely related to the broader HVDC Power Architecture trend in hyperscale facilities.