No GPU required: the case for CPU-first Physical AI at the edge

Robot computers are getting bigger, and for perception and large policies that makes sense. The decision layer, though, doesn't have to follow them. This piece argues for a compact, deterministic, CPU-first layer that learns skills, picks actions and checks them before they reach the motors, next to the GPU stack rather than in place of it.

· HiHolo · 8 min read

Line illustration: a glowing blue CPU chip wired to a robot arm that holds a cube, with a faded graphics card in the background
The decision layer on a CPU, next to the robot it drives; the GPU stays in the picture for the work that needs it. Illustration: HiHolo.

The edge is consolidating around big accelerators

On 22 October 2026, Agility Robotics announced that Digit 5, its next-generation humanoid, will standardize its onboard compute on NVIDIA IGX Thor modules, with NVIDIA as the exclusive onboard-compute provider for the general-availability version. Agility is also building NVIDIA Halos safety models into its safe human-detection system [1]. Agility's CTO described the move as giving Digit 5 "a common foundation" ahead of broad commercial deployment [1].

The reasoning is sound. When Agility first started working with Jetson Thor in 2025, it explained that whole-body control, manipulation and scene understanding all rely on deep learning, and that larger end-to-end policies and richer semantic perception need a lot of onboard computation [2]. If your robot runs big neural networks on camera streams, you need an accelerator.

But "the robot has a GPU" and "every part of the robot's intelligence should run on a GPU" are two different claims. The second one deserves a closer look.

Two different workloads on one robot

A modern robot stack does two kinds of work that have very different computational profiles.

Perception and generalist policies

Turning pixels into objects, or language and images into candidate motions, means dense tensor arithmetic over large models. This is what GPUs and AI accelerators are built for, and it is where they clearly earn their power and cost.

The decision layer

Once the robot has a structured picture of the world (poses, loads, contact states, masses, constraints), a different set of questions comes up. Which skill applies? What grip force stays within the limits? Is the action the policy proposes allowed in this state? Can we prove afterwards why the robot did what it did? These questions involve rules, small learned models, optimization and verification. They need correctness, repeatability and traceability far more than they need throughput.

The decision layer is the one buyers, integrators and safety reviewers ask about most. It is also the layer that gets hardest to reason about when it lives inside the same large probabilistic model that does perception.

A layered diagram. At the top, sensors and cameras feed a GPU or accelerator block for perception and VLA or neural policies, which proposes actions. Below it, a CPU-first Holo Engine decision layer covers skills, reasoning, optimization and verification, and checks proposed actions against explicit constraints. Verified actions go to the robot controller and actuators at the bottom. A side box shows that each decision leaves a trace of inputs, state and reasons that can be replayed. Sensors and cameras Raw signals: RGB-D, joint states, force, mass GPU / accelerator (where needed) Heavy perception, VLA or neural policies: propose actions CPU-first decision layer (Holo Engine) Skills · reasoning · optimization · verification Checks proposed actions against explicit constraints Robot controller and actuators Decision trace Inputs, state, reasons Replayable
Figure 1. A conceptual stack, not a benchmark. The GPU layer is dashed because many tasks need it and some don't. The decision layer is the part a CPU-first engine is designed for: it sits between whatever proposes an action and the hardware that executes it, and it logs why each action was allowed.

Why put the decision layer on a CPU

1. Budgets on real machines are finite

Mobile manipulators, quadrupeds and retrofitted industrial cells all have tight power, thermal, memory and cost limits. Every watt and megabyte spent on decision logic is taken away from perception, batteries or payload. A decision layer that fits comfortably next to the rest of the software, without needing its own accelerator, keeps those budgets for the work that really needs them.

2. Determinism is easier to get, and to prove

A decision layer an engineer can replay is a decision layer an engineer can test and reason about. Holo Engine is built around that: every decision can be replayed and audited [4], constraints are explicit, and teams can examine inputs, state and execution traces to see how a decision was reached, then repeat runs against fixed inputs and state to investigate unexpected behavior [3]. That is the kind of material engineering and compliance teams need for a safety review [3].

3. Fast fitting changes the iteration loop

If fitting a task model takes about a second instead of a training job, you can adjust a skill when the task, conditions or parameters change, without starting over and without booking cluster time [3].

4. Commodity hardware widens who can deploy

CPUs are everywhere: in industrial PCs, controllers and laptops. A compact runtime that runs "from cloud to edge" [4] can be tested through an API and then deployed on-premises or at the edge, close to the devices and sensors it serves [4].

What "compact" means in practice: our measurements

Claims about efficiency are only useful with their measurement context. The figures below come from HiHolo's robotics page and were measured in October 2026 on an Intel Core i9-9880H laptop CPU with 16 GB of system RAM [3].

≈1 sCPU model fitting: 0.83–1.16 s per Meta-World task model, from prepared state/action data
18scripted teacher demonstrations in the Panda experiment
0GPUs: fitting and control computation ran on CPU only
≈100 MBpeak process RAM for robot control and visual processing

What each number includes.
≈1 s: five separate Meta-World models, each fitted from 4,560–9,084 prepared state/action examples, took 0.8318–1.1641 s per model. Experience collection, perception and physics simulation are not included [3].
18 demonstrations: the Panda experiment used 18 scripted teacher demonstrations to learn two correction gains and a hold/increase readout. A task-specific adapter supplied geometry and physical execution. Collection plus fitting took about 7.1 minutes [3].
0 GPU: model fitting and control computation ran on CPU without GPU acceleration. Rendering and hardware-specific robot software are outside the measurement [3].
≈100 MB: peak process RSS of the Alphabet Lab runtime, remeasured on 28 October 2026 at 97.89, 104.67 and 104.85 MB. Each run recomputed 34,946 results and 32 RGB-D frames. The process covers Holo, the loaded models, HoloLanguage and RGB-D processing. The simulator, renderer, operating system and device drivers are excluded. 1 MB = 1,000,000 bytes [3].

Peak RAM per run

Bar chart. Three remeasured runs of the Alphabet Lab runtime peaked at 97.89, 104.67 and 104.85 megabytes. A dashed reference line marks 100 megabytes. 0 MB 30 MB 60 MB 90 MB 120 MB Run 1 97.89 MB Run 2 104.67 MB Run 3 104.85 MB ≈100 MB
Peak RSS, MB (1 MB = 1,000,000 bytes)Reference line

Fitting time range

Range chart. Five Meta-World task models took between 0.8318 and 1.1641 seconds each to fit on CPU. A dashed reference line marks 1 second. 0 s 0.35 s 0.7 s 1.05 s 1.4 s Fastest model 0.8318 s Slowest model 1.1641 s 1 s
Fitting time per model, seconds (prepared data; collection, perception, simulation excluded)Reference line
Figure 2. Data from the HiHolo robotics page footnote [3]: Intel Core i9-9880H, 16 GB RAM, October 2026. Peak RSS covers Holo, loaded models, HoloLanguage and RGB-D processing; simulator, renderer, OS and drivers are excluded. On the 16 GB test machine, even the highest peak is below 1% of system memory. The second panel shows the fitting-time range for the five Meta-World models (0.8318–1.1641 s).

For context, Holo Engine ships as a compact engine binary of roughly 15–25 MB depending on the platform. Learning, reasoning, optimization and verification run in that one engine instead of separate tools stitched together, which is a large part of why the footprint stays small [3][4].

Learning while working, on a laptop CPU

Fitting a model once is useful. Updating it during operation matters more at the edge. In our latest OpenArm V2 experiment, run 3 in MuJoCo simulation, Holo Engine predicted the mass of each pour from the scoop before it happened, with a mean error of 0.73 g across 173 pours. It also learned online during the task: 173 online updates took 9.7 s of engine time in total, on an Intel Core i9-9880H laptop CPU with no GPU. From one run to the next, even spread was reached in 5 of 8 test conditions instead of 3, losses stayed within limits in 7 of 8 instead of 3, and the full task criterion was met for the first time [5].

Where GPUs still make sense

CPU-first is not a claim that robots don't need GPUs. We think the opposite is often true:

  • Dense perception. High-resolution, multi-camera segmentation, detection and 3D scene understanding at high frame rates is accelerator work.
  • Large generalist policies. VLA and end-to-end manipulation models that map images and language to motion depend on large networks. Agility's case for Thor rests on exactly this [2].
  • Training at scale. Pre-training foundation models and running large reinforcement-learning campaigns in simulation still belongs on GPU clusters.

The practical question is not CPU or GPU. It is which layer needs which kind of compute, and which layer needs to be explainable. A neural policy can propose an action; a compact, deterministic layer can check that proposal against explicit constraints before execution [3]. That is a different job, and it doesn't need the same hardware.

Table 1. A rough division of labour. Qualitative, not a benchmark.
WorkloadTypical computeWhat matters most
Pixel-level perceptionGPU / acceleratorThroughput, latency per frame
VLA / neural policyGPU / accelerator or cloudGeneralization across tasks
Skill selection, parameter fittingCPU-firstFast adaptation, small data
Action verification against constraintsCPU-firstDeterminism, traceability, replay

CPU-only isn't the whole story

To be clear about what we are arguing: running on a CPU isn't a product on its own. Efficiency only matters when it comes with something buyers need: decisions that are repeatable, constraints that are explicit, and a trace that engineering and safety teams can inspect [3]. Holo Engine pairs the compact footprint with that verifiability. You can use it in three ways [3]:

Option 1
Action Verification
A verification layer on top of an existing VLA or neural control stack.
Option 2
Specialized Skills
Task-specific skills integrated into your existing control system.
Option 3
Full-Cycle Intelligence
Learning, reasoning, action selection and verification in one runtime tailored to your robot.
Let the accelerator see and propose. Let a compact, deterministic layer decide, verify and explain.

What comes next

Footprint, adaptation speed and verifiability are the questions we keep measuring. Our experiments confirm the approach; the next step is a pilot on a real robot with a robotics partner.

Every robot. A measurable outcome.

Tell us what your robot needs to do. Let's discuss a pilot.

hi@hiholo.ai

Sources and further reading

  1. Agility Robotics, "Agility Robotics Expands NVIDIA Collaboration as It Prepares Digit 5 for Commercial Scale", 22 October 2026. agilityrobotics.com
  2. Agility Robotics, "Agility Robotics Powering the Future of Robotics with NVIDIA Jetson Thor", 25 August 2025. agilityrobotics.com
  3. HiHolo, "Robotics & Autonomy — Holo Engine", including the measurement footnote (October 2026, Intel Core i9-9880H, 16 GB RAM). hiholo.ai/robotics
  4. HiHolo, "Holo Engine — Deterministic AI for Autonomous Systems". hiholo.ai
  5. OpenArm V2 run 3 figures (0.73 g, 173 updates in 9.7 s, run-over-run results): HiHolo OpenArm V2 experiment, run 3, MuJoCo simulation, October 2026.
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