About Delphi
Delphi is the Marin team's first open scaling suite, inspired by
Pythia.
It has three parts:
- a scaling recipe that maps compute budgets to model configurations,
- a scaling suite of models trained from that recipe at IsoFLOP budgets
from 3 × 10¹⁸ to 1 × 10²³ FLOPs, and
- a scaling law which uses the smaller Delphi models to predict the larger
ones.
A pre-registered forecast from that scaling law predicted the final loss of the
largest Delphi run (1 × 10²³ FLOPs, 25 B parameters, 600 B tokens) within
0.2%, using 300× less compute than the training run itself. The same
process forecasts downstream benchmarks — MMLU, HumanEval, and GSM8K — via a
two-step regression combining compute and observational scaling laws.
See "Scaling Laws That Extrapolate 300× Past the Fit"
for the recipe, fit, and downstream-eval projections. The full set of Delphi
checkpoints — IsoFLOP grid points, held-out optima at 1e21/1e22/1e23 with
multiple random seeds, and training intermediates — lives on
marin-community on the Hub.
Research artifact. This model has not been properly tested or evaluated and is not necessarily secure. Use at your own risk in production settings.
Model details
Table | |
|---|
| Architecture | Qwen 3 (pre-norm decoder, RMSNorm, RoPE, QK-norm with learned scaling, SwiGLU MLPs) |
| Parameters | 2,895,178,112 |
| Hidden size | 2432 |
| Layers | 24 |
| Attention heads | 19 |
| KV heads | 19 (no GQA) |
| Head dim | 128 |
| FFN intermediate | 9728 (MLP ratio 4) |
| Vocab size | 128,256 (Llama 3 tokenizer) |
| Max sequence length | 4096 |
| Position encoding | RoPE (θ = 500000, Llama 3-style scaling) |
| Bias terms | None |
| Tied embeddings | No |
Training
Table | |
|---|
| Compute | 5.5e20 FLOPs |
| Tokens | 29,916,397,568 |
| Steps | 57,061 |
| Training seed | 0 |
| Final export step (zero-based) | 57,060 |
| Sequence length | 4096 |
| Optimizer | AdamH (Adam with Hyperball) |
| Recipe | Delphi (Complete(d)P-style scaling with (T₀/T)^0.3 token-horizon LR correction) |
| LR schedule | WSD: 10% linear warmup, 20% linear decay, 0 floor |
| Precision | f32 master params, bf16 compute |
| Parallelism | FSDP |
| Data mixture | Nemotron-CC + StarCoderData + ProofPile 2 |
| Tokenizer | Llama 3 (vocab 128,256) |
AdamH, Adam
with Hyperball, constrains every projection weight to stay on the Frobenius-
norm sphere it was initialized on, so weight decay has nothing to regularize
away and falls out of the recipe. A Complete(d)P-style transfer rule with a
(T₀/T)^0.3 correction sets learning rate as token horizon grows. Reference
constants: B₀ = 64, T₀ = 2.5 B tokens, η₀ = 0.00630, η₀,Adam = 0.000656,
ε₀ = 1.85 × 10⁻⁸. Recipe code:
experiments/references/completed_adamh.py.
The recorded training configuration is in
experiments/references/train_delphi_seeds.py.
See the reproduction instructions
and the training run.
The linked code revision publishes the recorded recipe; it does not identify
the checkout used for the completed training run. The inference export has
architectures: ["Qwen3ForCausalLM"]; its weights are unchanged from training.
Companion releases
- All Delphi model checkpoints:
marin-community on the Hub.
- Plot data behind every figure in the blog post:
marin-community/delphi-blog-data (one config per figure, with wandb_url on every row).
- Pipelines that deterministically reproduce the training mixture from public
Nemotron-CC, StarCoderData, and ProofPile 2 sources: see the Marin repo.
Evaluation
Evaluation results for this checkpoint are not included in this release.
Limitations
- Trained on an English-heavy web mixture; no multilingual coverage.
- Pretrained-only — no instruction tuning, RLHF, or safety alignment.
- The Delphi recipe targets compute-optimal training, not inference-cost-aware
overtraining; for inference-heavy deployments, an overtrained smaller model
may be preferable. The blog's "off-optimal training" section quantifies the
penalty.
- This is one checkpoint in a much larger Delphi release; pick the one that
matches your compute / parameter / token regime, or browse the full set at
marin-community.
Citation: original Delphi recipe
@misc{held2026delphi, title = {Scaling Laws That Extrapolate 300× Past the Fit}, author = {Held, Will and {Marin Community}}, year = {2026}, url = {https://openathena.ai/blog/delphi}}