Performance & Systems Architect

About Majestic Labs

We’re a fast-moving, US-Israeli AI startup building next-generation infrastructure for the world’s most demanding AI workloads. Our mission is to accelerate the future of intelligence and make it ubiquitously accessible by delivering full stack custom AI servers optimized for large-scale inference and training.

Backed by top-tier investors and led by industry veterans, we’re scaling rapidly. We seek forward-thinking engineers and operators who thrive in a collaborative environment and excel at solving complex challenges from first principles. If you want to build infrastructure that fundamentally changes what the world can accomplish with AI, come join us!

About the position

We are looking for a Senior Architect to work on simulation and translating architectural ideas into quantitative, defensible performance models.

This role is ideal for someone who lives at the intersection of:

• Computer architecture
• Workload characterization
• System-level modeling
• AI / data-intensive workloads

Responsibilities

Performance simulator & translate workloads into models

• Extend and maintain system-level performance models (compute, memory, interconnect, scheduling).
• Model system behaviors: NUMA effects, contention, coherence, bandwidth saturation.
• Characterize real workloads (LLMs, GNNs, graph analytics, tabular models and more).

Guide architectural decisions

• Evaluate architectural trade-offs 
• Produce quantitative comparisons vs. existing and emerging AI platforms.
• Work closely with hardware architects, compiler/runtime teams, and external partners.
• Ensure simulator assumptions align with hardware and software reality.

Support external conversations

• Contribute to technical deep dives with strategic partners and customers.
• Help translate performance modeling into clear narratives for execs and investors.

Requirements

• BSc in CS, EE, CE or similar degrees plus 8 years experience in computer architecture, systems research, or performance engineering. Or PhD in CS, EE, CE or similar degrees plus 2 years of relevant experience. 
• Strong background in performance modeling or simulation (analytical, event-driven).
• Experience with AI or graph workloads.
• Understanding of: memory hierarchies (NUMA, caches, coherence), Interconnects (PCIe, fabrics, RDMA-), GPU-based systems.
• Hands-on coding experience (Python, C/C++, or similar).
• Ability to reason from first principles, not just benchmarks.

Preferred Qualifications

• Background in architecture simulators ( gem5-like, in-house tools, or research frameworks).
• Exposure to ML runtimes, compilers, or hardware-aware model design.
• Research background (MS/PhD) in computer systems (CS/EE), architecture, or related fields.

We seek smart, curious, self-driven individuals who enjoy creative problem-solving and continuous learning. Even if you don't meet all requirements, we'd love to hear from you if you have the mindset to tackle complex challenges.

Majestic Labs is an equal opportunity employer deeply committed to diversity of background and thought. If you are ready to dare greatly, learn from mistakes, engage in vigorous debates, and help create a step-function shift in human technical capability, we want to meet you!