700 W per GPU is the number everyone knows and it is only 40% of the answer. The chain from GPU TDP to node, to IT load, to facility power with PUE: about 1.8 MW, and what that means in racks and dollars.
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What is the power budget for a cluster of 1,024 H100s?
700 W per GPU is the number everyone knows and it is only 40% of the answer. The chain from GPU TDP to node, to IT load, to facility power with PUE: about 1.8 MW, and what that means in racks and dollars.
Updated Sep 2026 · Grounded in real AI infrastructure interview loops and written to a senior-engineer editorial bar, with every number worked and every diagram hand-built.
The concepts behind this question
Ranked by how closely each one overlaps this question's topic, so the first card is the thing to read if the answer above moved too fast.
Advanced
Power and Datacenter ConstraintsThe binding constraint on new GPU capacity in 2026 is not chips or capital but megawatts: an H100 node draws about 10 kW, a GB200 NVL72 rack about 120 kW, and a 100,000-GPU cluster needs on the order of 150 MW with cooling. This page converts GPU counts to power, power to cooling and facility requirements, and both to cost, so a candidate can size a training hall from a power budget and explain why liquid cooling, PUE and the local grid decide where the next cluster goes.🧮 Napkin Math & Capacity🔒 Premium
Foundational
Colocation, Power Contracts and Site SelectionFor most organizations the constraint on deploying GPUs is not the GPUs. It is finding a hall that can deliver 100 kilowatts or more per rack, reject that heat with liquid, and sign a contract for the power years before the hardware exists. Colocation contracts price reserved capacity rather than consumption, cooling capability is what eliminates most sites, and the lead time on new electrical supply is measured in years while GPUs arrive in months.🖧 Hardware & Cluster Build-Out
Foundational
Direct-to-Chip Liquid Cooling and CDUsAbove roughly 40 kW a rack cannot be cooled by air in any practical hall, which is why every dense GPU deployment now runs liquid to the chip. A cold plate sits on each GPU, a coolant distribution unit isolates the clean rack loop from facility water, and the facility side runs warm, typically 30 to 40 degrees supply, because warm water is cheaper to make. The design numbers are flow rate and temperature rise, and both fall out of one equation that every operator should be able to do from memory.🖧 Hardware & Cluster Build-Out
Foundational
Rack Power Delivery and BuswaysA GPU rack has gone from 10 kW to over 120 kW in a few generations, and the electrical design changed with it. At 132 kW on a 415 V three-phase feed a rack draws about 184 amps, which is past what a normal power strip carries, so distribution moves to overhead busway and the rack takes redundant high-current taps. On top of the steady draw sits a synchronized transient every training step, because thousands of GPUs finish a collective at the same instant, and that swing is what sizes the upstream equipment.🖧 Hardware & Cluster Build-Out
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FEDITOR'S NOTE
The interviewer wants the layers: GPU, host, network and storage, then PUE. A candidate who stops at 1,024 × 700 W has sized a third of the facility.
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