Rack-Scale AI Hardware Architect

Mythic builds AI compute platforms around large numbers of small, energy-efficient accelerators rather than a handful of very large ones. Serving frontier-scale models on that kind of architecture pushes the hardest engineering problems out of the die and into the rack: how many thousands of devices are packaged, connected, powered, and cooled in a very small volume. We are looking for a System Architect to own the rack-level reference design for these platforms. You will lead rack and platform pathfinding across board and chassis layout, scale-up and scale-out fabric topology, connector and cable plant, power delivery, and the cooling required at high rack densities. None of it can be settled apart from software: how a model is partitioned across devices sets the bandwidth required between layers, and the bandwidth the fabric can economically carry sets which partitionings are viable. The role sits at the intersection of electrical, mechanical, and software engineering, and the goal is an architecture quite different from today’s GPU racks that delivers a comparable result at rack level. What You’ll Own Rack-level reference architecture — board, chassis, backplane, rack topology, mechanical envelope, physical constraints, and serviceability — from pathfinding through a working reference implementation. Scale-up and scale-out interconnect: PCIe hierarchy and switching, high-speed Ethernet and SerDes, die-to-die and board-level links, copper versus optical at each tier, retimers, connectors and cable plant, topology, oversubscription, and the bandwidth and latency budget for each hop. Thermal architecture for high-density racks: direct-to-chip and cold-plate cooling versus immersion, CDUs and manifolds, flow and pressure budgets, component thermal limits, and the rack-to-facility interface. Power delivery architecture, including rack distribution and busbar design, high-voltage DC and 48V-class conversion and efficiency, transient behavior across very large device counts, redundancy, telemetry, and RAS. Joint modeling with the software team of the full LLM solution — partitioning strategy, inter-layer traffic, collectives — translated into fabric, memory, and topology requirements and backed by quantitative rack- and cluster-level models of performance, power, thermal, and cost. What We’re Looking For Minimum Bachelor’s degree in Electrical Engineering, Mechanical Engineering, Computer Engineering, or a related field, with relevant experience in server, datacenter, HPC, or AI system design. Demonstrated architecture and design ownership of dense, rack-based server systems taken to production, including authoring the specifications ODM and OEM partners build against. Expert command of state-of-the-art copper and optical interconnect: PCIe, high-speed Ethernet and SerDes, DAC and twinax, backplane and cabled channels, AOCs, and pluggable or co-packaged optics, with the signal-integrity judgment to know where each approach stops working. Expert command of removing heat from racks, cooling architecture, cold plates, manifolds, CDUs, flow and thermal budgeting, and the facility-side interface. Ability to reason across interconnect, power, thermal, mechanical, and software boundaries rather than within one, including working directly with software on model partitioning, with a track record of modeling and trade studies driving architectural decisions. Preferred Qualifications Master’s degree or PhD in Electrical Engineering, Mechanical Engineering, Computer Engineering, or a related field. Hyperscale or OCP experience, including ORv3 and contributions to relevant standards bodies. Experience with systems built from many small accelerators, dataflow, or wafer-scale architectures rather than only GPU-tray designs. Experience with LLM training or inference at scale and how parallelism strategies stress a fabric, plus familiarity with chiplets, die-to-die interfaces, and advanced packaging. Experience carrying a reference design through ODM or CM partners into production and into customer datacenters, including EMC, structural, and shock and vibration qualification. What Success Looks Like A rack reference implementation exists, is buildable, and meets its performance, power, and thermal targets in hardware rather than in a spreadsheet. The partitioning and fabric story is coherent: software can map frontier-scale models across the system, and the interconnect carries the resulting traffic without being over-provisioned or starved. Thermal and power architectures are validated with measured data, hold headroom for the next device generation, and match a system model trusted for the next round of decisions. Customers and partners can deploy the design in real facilities against clearly documented power, cooling, weight, and service requirements. Hardware, mechanical, and software teams work from one architecture instead of three. Why This Role Matters Mythic's advantage is energy per operation at the device. Delivering that advantage at scale depends on the rack around it — how it powers, cools, and moves data between a very large number of devices. At this density the binding constraints are rack-level: fabric topology, connector and cable plant, power distribution, and thermal. Getting them right is what turns device-level efficiency into rack-level performance. Model partitioning and fabric design are the same decision viewed from two directions. This role is where that decision gets made. If you want to define what an AI rack looks like when it is not built around a handful of kilowatt-class GPUs, we should talk. Why Mythic Define the rack architecture for a fundamentally different approach to AI compute. Own foundational decisions with direct influence on silicon, packaging, systems, software, and product strategy. Work across the full stack, from model partitioning and interconnect down to busbars, cold plates, and connectors. Join a highly collaborative team solving difficult engineering problems across silicon, package, board, firmware, software, and systems. Have outsized technical impact in a senior individual-contributor role with broad organizational visibility. Mythic is committed to building an inclusive team and encourages candidates from all backgrounds to apply. #J-18808-Ljbffr