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Case study, modelled

The site that is full

We are full, and there is silicon in the yard.

Modelled

272 installed racks release about 1,279 kW inside a 12 MW envelope, room for 32 racks against 24 waiting in the yard. The site then draws less than before while carrying about 9 per cent more accelerators, modelled.

A 12 MW site sits at its envelope with 272 racks installed and 24 racks of accelerators in the yard. Managing the installed fleet releases about 1,279 kW on the conservative reading, room for 32 racks, so all 24 yard racks are energised, modelled. The site then draws less than it did before while carrying about 9 per cent more accelerators.

Who it is for

A neocloud or GPU cloud operator with a fully allocated site. The operator signs; the change-control and security reviewer decides.

GPU cloud and neocloud

The basis

This is modelled

This is modelled. Every rack, megawatt and pound here is arithmetic over inputs you can change. One number is ours, and it is measured: up to 21% less GPU die power on NVIDIA H100 NVL over 48 hours. Managed and baseline arms ran under an equal cap, read as NVML die power. Die power is a lower bound on wall power. This model runs on a different Hopper part, so the transfer is modelled until a baseline run on that part. A three-week validation on your own fleet makes the figure yours.

Key figures

Every figure, what kind of figure it is, and its basis.

One figure is measured. The derived and observed figures come from the same run. Everything else is modelled on the inputs below.

  • GPU die power reduction

    measured

    Up to 21% less

    NVIDIA H100 NVL, one continuous 48-hour run, managed and baseline arms under an equal cap, NVML die power.

  • Tokens per watt

    derived

    Up to +22%

    NVML die power and vLLM serving throughput on the same 48-hour run, Balanced mode.

  • Throughput change in the run

    derived

    0%

    Same 48-hour run, Balanced mode, throughput and P99 latency held.

  • Die temperature

    observed

    10 to 15 degrees C cooler

    At the die, from the same run; counted separately from the money on this page.

  • Reduction at the rack input

    modelled

    About 11 per cent conservative; 21 per cent stated basis

    21% times the about 51 per cent accelerator share, cascade factor one. The stated basis treats the die figure as a floor on wall watts.

  • Watts released by the installed 272 racks

    modelled

    About 1,279 kW to about 2,513 kW

    11,968 kW of installed draw times the rack-input reduction, no hardware added.

  • Racks the released watts hold

    modelled

    32 racks (1,024 accelerators) to 72 racks (2,304 accelerators)

    Released watts over the managed rack draw, rounded down to whole racks.

  • Yard stock absorbed

    modelled

    All 24 racks on both readings, with 8 to 48 racks spare

    32 or 72 racks held against 24 owned and waiting.

  • Accelerators after the yard stock is energised

    modelled

    9,472, up about 9 per cent

    8,704 installed plus 768 from the yard.

  • Site draw after the yard stock is energised

    modelled

    About 11,632 kW conservative; about 10,289 kW stated basis; 11,968 kW before

    296 racks at the managed rack draw. Less power while carrying more accelerators.

  • Gross revenue on the 768 yard accelerators

    modelled

    About GBP 8m to GBP 11m a year at the declared band

    768 accelerators at the illustrative band. A second route, filed operator revenue per megawatt of active power, puts the same watts at about GBP 5.7m to GBP 5.9m a year; plan against that lower figure.

  • Energy line if the released watts are banked

    modelled

    About GBP 940,000 a year at a 40 per cent load factor; up to about GBP 2,350,000 at nominal draw

    About 1,279 kW over 8,760 hours at about 21 pence. In the case modelled the watts go to the yard stock instead.

  • Overdraw on a total release after the yard stock is energised

    modelled

    1,024 kW, about 9 per cent over the envelope

    296 racks at 44 kW is 13,024 kW against 12,000 kW. About 79 racks would have to release at once to breach it.

  • Break-point accelerator share

    modelled

    About 39 per cent

    Below it the released watts no longer hold the 24 yard racks on the conservative reading.

  • The same logic at ten times the scale

    modelled

    120 MW, 2,727 racks, 326 racks held, about GBP 85m to GBP 106m a year on the yard stock at the declared band

    Every ratio is scale-invariant because the runtime acts per accelerator. The total-release overdraw grows to about 10,548 kW.

Declared inputs

What the arithmetic runs on.

Each input is stated with its basis. Change any of them and the figures above move with it.

  • Site envelope

    12 MW of IT load at the rack input

    Reader-supplied. If it is total facility power, your power usage effectiveness is required.

  • Rack draw at the rack input, nominal

    44 kW

    Reader-supplied. It includes host processors, network fabric, switching and power conversion, none of which the runtime addresses.

  • Accelerators per rack

    32

    Reader-supplied. Four 8-way systems per rack.

  • Accelerator board power

    700 W

    NVIDIA H100 SXM, Hopper, published board power.

  • Accelerator share of rack draw

    About 51 per cent

    Derived: 32 accelerators at 700 W over 44 kW. The largest lever in the model, and yours to set.

  • Upstream cascade factor

    1, no credit

    Default. It gives our own physics argument no credit.

  • Accelerators already owned and unenergised

    24 racks, 768 accelerators

    Reader-supplied. The yard stock.

  • Revenue per accelerator a year

    About GBP 11,000 to GBP 14,000, illustrative

    Your own figure, at 85 per cent of hours let over 8,760 hours.

  • Load factor for the energy line

    40 per cent, with 100 per cent as an upper bound

    Reader-supplied. Capacity is computed on provisioned draw; energy on consumed energy.

  • Electricity cost, energy line only

    About 21 pence a kilowatt-hour

    DESNZ published non-domestic Extra Large band, Q1 2026, excluding the Climate Change Levy.

  • Operating mode

    Balanced

    The mode the coefficient was measured in, with throughput and P99 latency held.

  • Coefficient at the die

    21 per cent

    Measured. Fixed. Not an input.

The working

The situation

An operator runs one site, and the site is at its envelope. The sales team quotes lead times instead of capacity. In the yard sit accelerators the operator has already bought and cannot energise, because there are no watts left. The usual answers are slow or expensive. A new grid connection is measured in years, new plant in quarters, and a second site restarts procurement and splits the fabric. None produces a watt this quarter, and the yard stock depreciates whether or not it earns.

The declared inputs

The envelope is 12 MW of IT load at the rack input. Racks draw 44 kW nominal and carry 32 NVIDIA H100 SXM accelerators at 700 W board power. Accelerators are therefore about 51 per cent of rack draw: the largest lever in the model, set from your own two numbers. The cascade factor defaults to one, no credit to our own physics argument. The yard holds 24 racks, 768 accelerators. Revenue is an illustrative GBP 11,000 to GBP 14,000 per accelerator a year, at 85 per cent of hours let.

The plane arithmetic, in two readings

Our coefficient is at the accelerator die and your constraint is at the rack input. Between them is the accelerator share, so the reduction at the rack is the die figure times that share and the cascade factor. The conservative reading applies the die figure to the accelerator share alone and returns about 11 per cent at the rack. The stated basis treats the die figure as a floor on wall watts and returns 21 per cent. Both travel together as a range, modelled.

Today 272 racks fit the envelope: 8,704 accelerators drawing 11,968 kW, with 32 kW to spare. Managed, the same 272 racks release about 1,279 kW on the conservative reading and about 2,513 kW on the stated basis. No hardware is added. At the managed rack draw those watts hold 32 racks and 1,024 accelerators, or 72 racks and 2,304 accelerators. The yard stock is 24 racks, so it fits on the conservative reading with 8 racks to spare, and with 48 on the stated basis, modelled.

The site after the retrofit

After the retrofit, with all 24 yard racks energised, the site carries 296 racks and 9,472 accelerators, about 9 per cent more than today. On the conservative reading it draws about 11,632 kW against 11,968 kW before. Less power, more accelerators, modelled. On the stated basis the draw is about 10,289 kW. The 32 kW the site already sat under its envelope is deliberately not spent: it is the model's only reserve, and the reviewer will ask why.

Where the money comes from

The 768 yard accelerators earn about GBP 8m to GBP 11m a year gross at the declared band, modelled. A second route with no shared inputs, filed operator revenue per megawatt of active power, puts the same watts at about GBP 5.7m to GBP 5.9m a year. Plan against that lower figure, with your own revenue per megawatt in it. The revenue is new: it does not exist without the released watts, because the accelerators that earn it cannot be energised without them.

There is no capital line: no hardware, no construction, no permits. The runtime installs in hours as a software deployment, driver-adjacent, and adds no draw of its own. Revenue begins when the racks are let, on your own installation and sales timeline, not when the software is installed.

Tokens per watt, and the energy line

ADAPT holds throughput while cutting power. The run gave up to +22% tokens per watt, derived from NVML die power and vLLM serving throughput, with 0% throughput change, derived. On a fixed fleet that gain is the energy line in another unit: the same tokens for less energy. Here the released watts go further and energise the 768 yard accelerators, a capacity effect counted separately and never multiplied with it.

In the case modelled here the released watts go to the yard stock and earn its revenue. Banked instead, about 1,279 kW at a 40 per cent load factor is about 4,483,000 kWh a year. At the DESNZ published non-domestic Extra Large band that is about GBP 940,000, modelled. At nominal draw every hour it is about GBP 2,350,000, an upper bound. Where power is passed through to tenants, the lower bill is theirs and the released capacity to energise more accelerators stays with the operator.

The two conditions

Two properties of your site decide the result. First, the binding limit. Is it a demand or energy figure measured over a settlement interval, or the rating of installed plant? A sustained reduction relieves the first. Plant is sized for the peak the racks can draw, and a sustained reduction does not relieve a plant rating. We free mean watts, and whether mean watts are sellable is the first question we ask.

Second, the duty cycle. A site can be fully allocated on power while its accelerators average well under half utilisation. Power is allocated on provisioned draw, and utilisation is measured on time. The mechanism lives in that gap: duty-cycle intelligence on bursty fleets. Most of the saving is idle-floor reduction, and most of the rest is clock-down at mid utilisation. On a fully saturated fleet it does not transfer.

The reviewer's question

The runtime fails open to full performance on a component fault; the workload comes first. The retrofit alone carries no exposure, since 272 racks at nominal draw sit inside the envelope. Exposure appears only when released watts are spent on hardware. At 296 racks, nominal draw is 13,024 kW, 1,024 kW over the envelope, about 9 per cent, modelled. About 79 racks, about 27 per cent of the fleet, would have to release at once to reach it. So the commitment is set below the measured floor with the reserve held back. Ceiling enforcement at the site is part of the first conversation.

What would change it

What moves the result, and how to check it on your own fleet.

The accelerator share of rack draw moves the result most, and it comes from two numbers you already hold. Multiply board power by accelerators per rack, then divide by the rack's nominal draw. On these inputs it is about 51 per cent, and the yard stock stops fitting below about 39 per cent. The share can fall by a quarter of its own value before the answer changes, modelled. Behind it sits the coefficient itself: at half the published figure the released watts still energise 15 of the 24 yard racks, and the figure your fleet reaches depends on its idle and mid-utilisation time. A three-week validation on your own instruments, at the rack input and concurrently with NVML, replaces every figure of ours on this page with yours.

Your own numbers

The same arithmetic, on your site.

Bring your envelope, your rack draw and accelerator count, your yard stock and the date you need the watts. We will run this arithmetic on your inputs and set up the validation on your own instruments.