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Subconscious vs Modal
Modal rents GPUs so you can build a serving stack. Subconscious is that stack, finished and tuned for long-horizon agents, as a managed API or on your own hardware.
By The Subconscious Team · Updated
Subconscious vs Modal: key differences
Modal is compute, not a model service. It has no catalog and no per-token price. A team decorates a Python function with the GPU it needs, brings its own weights and serving code, and pays by the second, from $0.59 an hour for a T4 to $3.95 for an H100 at list. Running a long-context agent on Modal means choosing and tuning the serving stack yourself, such as an open LLM on vLLM. Subconscious is the piece that would replace that stack. Its runtime drops in for vLLM or SGLang, prunes the KV cache, and delivers 2x faster task completion and a 5M+ effective context window, and it comes with a managed API billed on processed tokens.
Modal wins wherever the workload is not a long LLM trace: embeddings, reranking, transcription, OCR, media jobs, fine-tuning and agent sandboxes, all on one platform with $30 of free credits every month. Its catches show up at production scale, since non-preemptible US capacity runs about 3.75x list, and cold starts push teams into keeping containers warm. For a coding or research agent, Subconscious removes the serving work entirely, and its dedicated or on-prem options cover teams that still want their own hardware. Many stacks could use both, with Modal for tools and sandboxes and Subconscious for the model.
What Subconscious and Modal do
Subconscious
Subconscious is an MIT CSAIL spinout in Kendall Square that builds inference for long-horizon agents, the workloads where a single trace runs past 200K tokens and often into the millions. Its runtime drops in as a replacement for vLLM or SGLang. Instead of rereading an ever-growing context on every step, it prunes the KV cache and preserves suffix state, and Subconscious co-designs the runtime with post-trained model variants it calls Marathon. Against open models on standard inference, Subconscious delivers 2x faster task completion, delivers a 5M+ effective context window, cuts cost 50% and up to 80%, and scores neutral to 10% better on agentic benchmarks.
Example models: GLM 5.3, DeepSeek V4.1 Flash
Full Subconscious profileModal
Modal is serverless compute with GPUs attached. A developer decorates a Python function with the hardware it needs, such as gpu="H100", and Modal builds the container, schedules it, autoscales it and scales it back to zero. Billing runs per second with no minimum increment, from $0.59 an hour for a T4 to $3.95 for an H100 at list. Containers can hold up to 8 GPUs across T4 through B300.
Example models: none hosted by default; teams deploy their own, such as open LLMs on vLLM or Whisper
Full Modal profileShould you choose Subconscious or Modal?
Subconscious
Choose Subconscious for
- Long-horizon agents without building a serving stack
- A drop-in replacement for vLLM or SGLang on long traces
- Processed-token billing instead of paying for warm GPUs
Modal
Choose Modal for
- Bursty GPU jobs like embeddings, transcription and OCR
- Custom or fine-tuned models with your own serving code
- Agent sandboxes and batch jobs on per-second billing
Subconscious vs Modal at a glance
| Attribute | Subconscious | Modal |
|---|---|---|
| Model access | Open weights | Bring your own weights |
| Flagship models | GLM 5.3, DeepSeek V4.1 Flash | None hosted |
| Speed | 2x faster task completion | ~1s container boot |
| Price | 50–80% lower cost; billed on processed tokens | Per second; H100 $3.95/hr list |
| Customization | Marathon post-trained variants | Run any training code |
| Deployment | Managed API, dedicated, on-prem | Serverless GPU containers |
| Long context | 5M+ effective context | Depends on the model you deploy |
Frequently asked questions
What is the difference between Subconscious and Modal?
Modal rents GPUs so you can build a serving stack. Subconscious is that stack, finished and tuned for long-horizon agents, as a managed API or on your own hardware.
When should I choose Subconscious over Modal?
Long-horizon agents without building a serving stack; A drop-in replacement for vLLM or SGLang on long traces; Processed-token billing instead of paying for warm GPUs.
When should I choose Modal over Subconscious?
Bursty GPU jobs like embeddings, transcription and OCR; Custom or fine-tuned models with your own serving code; Agent sandboxes and batch jobs on per-second billing.
Is Subconscious or Modal cheaper?
Subconscious: 50–80% lower cost; billed on processed tokens. Modal: Per second; H100 $3.95/hr list. The cheaper choice depends on the model and workload.
Which has more context, Subconscious or Modal?
Subconscious: 5M+ effective context. Modal: Depends on the model you deploy.
Related comparisons
Run your longest agent traces on Subconscious
Point the OpenAI or Anthropic SDK, or the coding agent you already use, at Subconscious. Keep Modal for the work it does best and send the long runs to us.