What are the hardware requirements for OpenThinker3 1.5B?

OpenThinker3 1.5B requires approximately 3.1 GB of VRAM and supports a context window of 32K tokens. Quantized variants may run on less VRAM; see the Quantized Models section on this page.

Who developed OpenThinker3 1.5B and how large is it?

OpenThinker3 1.5B is developed by open-thoughts, a model with 1.5b parameters. The model is published as open weights on Hugging Face and indexed on LLM Explorer with full benchmark history.

Where can I download or evaluate OpenThinker3 1.5B?

OpenThinker3 1.5B is hosted on Hugging Face and linked from this page. LLM Explorer also lists quantized variants and similar alternatives if available.

OpenThinker3 1.5B by open-thoughts — VRAM 3.1GB, 32K context

Name: OpenThinker3 1.5B
Author: open-thoughts

OpenThinker3 1.5B is an open-source language model by open-thoughts. Features: 1.5b LLM, VRAM: 3.1GB, Context: 32K, License: apache-2.0, Instruction-Based, LLM Explorer Score: 0.19.

Arxiv:2506.04178 Base model:finetune:qwen/qwen2... Base model:qwen/qwen2.5-1.5b-i... Conversational Dataset:open-thoughts/openthou... Endpoints compatible Full Generated from trainer Instruct Llama-factory Qwen2 Region:us Safetensors

Model Card on HF 🤗: https://huggingface.co/open-thoughts/OpenThinker3-1.5B

OpenThinker3 1.5B Parameters and Internals

LLM Name	OpenThinker3 1.5B
Repository 🤗	https://huggingface.co/open-thoughts/OpenThinker3-1.5B
Base Model(s)	Qwen/Qwen2.5-1.5B-Instruct Qwen/Qwen2.5-1.5B-Instruct
Model Size	1.5b
Required VRAM	3.1 GB
Updated	2026-07-25
Maintainer	open-thoughts
Model Type	qwen2
Instruction-Based	Yes
Model Files	3.1 GB 0.0 GB
Model Architecture	Qwen2ForCausalLM
License	apache-2.0
Context Length	32768
Model Max Length	32768
Transformers Version	4.46.1
Tokenizer Class	Qwen2Tokenizer
Padding Token	<\|endoftext\|>
Vocabulary Size	151936
Torch Data Type	bfloat16
Errors	replace

Rank the OpenThinker3 1.5B capabilities

Have you tried this model? Rate its performance — this feedback helps the ML community find the right model for their needs.

Instruction Following and Task Automation
Factuality and Completeness of Knowledge
Censorship and Alignment
Data Analysis and Insight Generation
Text Generation
Text Summarization and Feature Extraction
Code Generation
Multi-Language Support and Translation

Best Alternatives to OpenThinker3 1.5B

Best Alternatives	Context / RAM	Downloads	Likes
Qwen2.5 1.5B 1.3M Stretched	1280K / 3.1 GB	12	0
Merge Cord V1	128K / 3.1 GB	155	1
Gte Qwen2 1.5B Instruct	128K / 7.1 GB	1006596	237
AceInstruct 1.5B	128K / 3.5 GB	139	22
... Abliterated TIES Qwen2.5 1.5B	128K / 3.5 GB	15	0
Saba1 1.8B	128K / 3.6 GB	6	1
Miniclaus Qw1.5B UNAMGS	128K / 3.5 GB	12	8
Bellatrix 1.5B XElite	128K / 3.5 GB	19	3
GCIRS Reasoning 1.5B R1	128K / 3.5 GB	9	1
...illed Scout 1.5B Instruct Gen1	128K / 3.5 GB	10	0

Note: green Score (e.g. "73.2") means that the model is better than open-thoughts/OpenThinker3-1.5B.