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Open-weight model · Text generation

Prochlo-190M-Base

by CyanoAI CyanoAI/Prochlo-190M-Base

Prochlo-190M-Base is an open-weight model for text generation from CyanoAI, released under Apache License 2.0. It has 190M parameters and a 4,096-token context. At 16-bit it needs about 0.5 GB of GPU memory, which fits on 1x MI300X from $1.85 an hour, at the lowest prices in the SAVRN Index. It draws 303 downloads a month.

The smallest and first model from CyanoAI — a 190.5M-parameter dense English base LM. Named after Prochlorococcus, the tiniest and most oxygen-producing photosynthetic organism on Earth: small, dense, and outproducing everything its size.

Parameters190M
Context4,096
Weights380.9 MB
Licenseapache-2.0
AccessOpen weights
Monthly Downloads303

Runs On

What it takes to serve Prochlo-190M-Base (190M parameters): the memory its weights need at each precision, and the cheapest way to rent enough data-center GPUs to hold them.

PrecisionWeightsMemory neededCheapest setupPer hourAlso fits
16-bit 0.4 GB 0.5 GB 1x MI300X (192 GB)
Vultr
$1.85 1x H100 $1.99 · 1x MI325X $2.00
8-bit 0.2 GB 0.2 GB 1x MI300X (192 GB)
Vultr
$1.85 1x H100 $1.99 · 1x MI325X $2.00
4-bit 0.1 GB 0.1 GB 1x MI300X (192 GB)
Vultr
$1.85 1x H100 $1.99 · 1x MI325X $2.00

Memory is the weights at that precision plus 20% for the runtime and a short context; a long context needs more. Prices are the lowest on-demand hourly rates in the SAVRN Index, read Oct 18, 2026.

Prochlo-190M-Base on every accelerator the SAVRN Index prices, at every precision

Model Card

By CyanoAI, published under apache-2.0, revision 9c6190d0a075.

The smallest and first model from CyanoAI — a 190.5M-parameter dense English base LM. Named after Prochlorococcus, the tiniest and most oxygen-producing photosynthetic organism on Earth: small, dense, and outproducing everything its size. All variants share the same architecture, tokenizer, and vocabulary, so they are drop-in interchangeable. Training corpus: a curated ~826GB English mixture (web / books / code / reference), stream-packed with the tokenizer jointly shipped in this repo. This is a base model — it speaks fluent Wikipedia-style prose but has not been aligned. For chat or assistant behaviour, start from the SFT or aligned variants. Zero-shot on wikitext (JSON subset, ~500k…

Read CyanoAI's full model card

The smallest and first model from CyanoAI — a 190.5M-parameter dense English base LM. Named after Prochlorococcus, the tiniest and most oxygen-producing photosynthetic organism on Earth: small, dense, and outproducing everything its size.

Model family

Repo Stage Status
CyanoAI/Prochlo-190M-Base Pre-trained base this repo
CyanoAI/Prochlo-190M-SFT Supervised fine-tune available
CyanoAI/Prochlo-190M Preference-aligned (DPO + RLAIF) in training

All variants share the same architecture, tokenizer, and vocabulary, so they are drop-in interchangeable.

Model at a glance

Parameters 190.5M dense (untied embeddings)
Architecture LLaMA-style decoder: RMSNorm, RoPE (θ=1e5), SwiGLU, no biases, per-head QK RMSNorm
Shape 12 layers × dim 768, 12 heads, hidden 3072
Vocab 50,261 (GPT-2 BPE + 4 control tokens)
Context 1024
Precision FP16
Format Safetensors, loads with Qwen3ForCausalLM (architecture-compatible; trained from scratch by CyanoAI, not derived from Qwen)

Pretraining

Tokens ~7.7B
Steps 300,000
Optimizer Muon (2D matrices) + AdamW
Schedule lr 1e-3, warmup 64, linear decay
Final train loss 1.7947 (ppl ≈ 6.0)
Final eval loss 1.6205 (ppl ≈ 5.06, still descending)

Training corpus: a curated ~826GB English mixture (web / books / code / reference), stream-packed with the tokenizer jointly shipped in this repo.

Intended use

This is a base model — it speaks fluent Wikipedia-style prose but has not been aligned. For chat or assistant behaviour, start from the SFT or aligned variants.

Load

from transformers import AutoModelForCausalLM, AutoTokenizer

tok = AutoTokenizer.from_pretrained("CyanoAI/Prochlo-190M-Base")
model = AutoModelForCausalLM.from_pretrained("CyanoAI/Prochlo-190M-Base", dtype="float16")

Evaluation

Zero-shot on wikitext (JSON subset, ~500k tokens): ppl ≈ 109.7. Not directly comparable to GPT-2-series numbers — different training distribution.

License

Apache 2.0

Configuration

Context length (tokens)
4,096
Layers
12
Hidden size
768
Feed-forward size
3,072
Attention heads
12
Key/value heads
12
Head dimension
64
Vocabulary size
50,257
RoPE base
100000
Model type
qwen3

Identity and Version

Repository
CyanoAI/Prochlo-190M-Base
Publisher
CyanoAI
Task
Text generation
Modality
Text
Library
Not stated by the source
Parameters
190M parameters
Languages
en
Revision
9c6190d0a0755ca77527a3c03a973e938d5d259e
First published
2026-10-05
Last updated
2026-10-07

Files and Weights

5 files, 384.5 MB in total. The weights are 1 file totalling 380.9 MB in safetensors.

Weights1 file · 380.9 MB
Configuration1 file · 1.0 KB
Tokenizer1 file · 3.6 MB
Documentation1 file · 2.4 KB
Repository1 file · 1.5 KB
Every file
FileTypeSizeSHA-256
model.safetensorsWeights380.9 MB 97eaaebe314f
config.jsonConfiguration1.0 KB —
README.mdDocumentation2.4 KB —
.gitattributesRepository1.5 KB —
tokenizer.jsonTokenizer3.6 MB —

License and Download

License
apache-2.0
Access
Open weights, no gate
Download size
380.9 MB
Download from CyanoAI

Released by CyanoAI through its official repository on Hugging Face. Read the license.

Memory Requirements

PrecisionWeights in memory
As published380.9 MB
16-bit0.4 GB
8-bit0.2 GB
4-bit0.1 GB

Weights only, from the published parameter count; the key-value cache and runtime add to this.

Built on This Model

Questions About Prochlo-190M-Base

How much GPU memory does Prochlo-190M-Base need?

About 0.5 GB at 16-bit and 0.1 GB at 4-bit: the weights (190M parameters) plus a working margin. A long context needs more.

What is the cheapest GPU to run Prochlo-190M-Base on?

At 16-bit, 1x MI300X from $1.85 an hour; at 4-bit, 1x MI300X from $1.85 an hour, at the lowest on-demand prices the SAVRN Index lists.

Can I use Prochlo-190M-Base commercially?

Yes. Prochlo-190M-Base is released under Apache License 2.0. The Apache License 2.0 is a permissive open-source license. It permits commercial use, modification and redistribution. It requires keeping the license and copyright notices and any NOTICE file, stating significant changes, and it includes an express patent grant from contributors.

What is Prochlo-190M-Base's context length?

4,096 tokens, from the maximum position embeddings in its published configuration.

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Open weights 194M parameters transformers

This is the model card of a transformers model that has been pushed on the Hub. Users (both direct and downstream) should be made aware of the risks, biases and limitations of the model. Use the code below to get started with the model. Carbon emissions can be estimated using the Machine Learning Impact calculator presented in Lacoste et al. (2019).

Open weights 194M parameters transformers

This is the model card of a transformers model that has been pushed on the Hub. Users (both direct and downstream) should be made aware of the risks, biases and limitations of the model. Use the code below to get started with the model. Carbon emissions can be estimated using the Machine Learning Impact calculator presented in Lacoste et al. (2019).

Open weights 194M parameters transformers