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Qwen3.5 Fine-Tuning Guide

unsloth.ai

31–40 of 118 posts

Re: Qwen3.5 Fine-Tuning Guide

#31
post #6

Fine tuning is a story that is nice to tell but that with modern LLMs makes less and less sense. Modern LLMs are so powerful that they are able to few shot learn complicated things, so a strong prompt and augmenting the generation (given the massive context window of Qwen3.5, too) is usually the best option available. There are models for which fine tuning is great, like image models: there with LoRa you can get good…

For agentic coding, which do you prefer:

a) qwen3-coder

b) qwen3.5 (general)

Re: Qwen3.5 Fine-Tuning Guide

#32
post #6

Fine tuning is a story that is nice to tell but that with modern LLMs makes less and less sense. Modern LLMs are so powerful that they are able to few shot learn complicated things, so a strong prompt and augmenting the generation (given the massive context window of Qwen3.5, too) is usually the best option available. There are models for which fine tuning is great, like image models: there with LoRa you can get good…

For me, trying to fine-tune a model to write "best day" prose I would accept over 80% of the time.

You are correct if we are talking about knowledge.

However it is bad at hyper-idiosyncratic, gritty style transfer.

I first noticed the issue when asking claude code to draft email responses. The choice of register was off. ("Register in writing refers to the level of formality and tone chosen to suit a specific audience, purpose, and context.")

I decided to talk all my HN comments and rewrite them in various bad LLM prose, and see if I could use DSPy to optimize a prompt using in-context-learning (ICL, I give it 10 examples of my HN comments) and the results were abysmal. RHLF fine-tuned frontier LLMs have a deep seated aversion to the target stylistic distribution of my comments.

I tried fine-tuning qwen3, llama, and gemma models. Instruct models are already so tuned that they could not be tuned. This is using several hunded comments as gold targets and 5 different LLM degradations per gold as the input.

Re: Qwen3.5 Fine-Tuning Guide

#37
post #9

Earlier quoted context omitted.

Only to prompt thought on this exact question, im interested in answers: I just ran a benchmark against haiku of a very simple document classification task that at the moment we farm out to haiku in parallel. very naive same prompt system via same api AWS bedrock, and can see that the a few of the 4b models are pretty good match, and could be easily run locally or just for cheap via a hosted provider. The "how much d…

if you add 2 spaces at the start of the line, you turn it into a code block like this

  | Model | DocType% | Year% | Subject% | In $/MTok |

  |----------------|----|-----|----|-------|

  | llama-70b -----| 83 |  98 | 96 | $0.72 |

  | gpt-oss-20b ---| 83 |  97 | 92 | $0.07 |

  | ministral-14b -| 84 | 100 | 90 | $0.20 |

  | gemma-4b ------| 75 |  93 | 91 | $0.04 |

  | glm-flash-30b -| 83 |  93 | 90 | $0.07 |

  | llama-1b ------| 47 |  90 | 58 | $0.10 |

Re: Qwen3.5 Fine-Tuning Guide

#38

Earlier quoted context omitted.

These are fair points considering LLMs are getting smarter and better every week - but to be fair the biggest benefits of finetuning / RL are still not yet realized: 1. If we have robots at home, they need some sort of efficient continual learning, which could be on the go finetuning / RL via some small LoRA - this will need to do multimodal finetuning with sparse reward signals - one could also imagine all data is a…

I work on Gemma and Gemini models I want to echo Daniel's point here. Small finetuned models have their place even with larger general purpose models. For example last year with Daniel/Unsloth's help we released a tiny specialized model that can get equivalent to Gemini level purpose specifically for FC. For folks that need efficient limited purpose models small models like this can fit a specific need. https://blog.…

Function calling and also finetuning with FC is a big use-case across any companies - we constantly see large orgs have internal APIs with some schema, and JSON guided output is good, but finetuning with FC is just much more powerful since the model actually starts to understand how to utilize the tools more effectively!

Nice work with Gemma and Gemini as usual! :) Excited for more cool models this year!

Re: Qwen3.5 Fine-Tuning Guide

#39
post #9
post #2

What are some sample real world cases folks are using to fine tune their own small/medium models?

Only to prompt thought on this exact question, im interested in answers: I just ran a benchmark against haiku of a very simple document classification task that at the moment we farm out to haiku in parallel. very naive same prompt system via same api AWS bedrock, and can see that the a few of the 4b models are pretty good match, and could be easily run locally or just for cheap via a hosted provider. The "how much d…

Labeling or categorization tasks like this are the bread and butter of small fine tuned models. Especially if you need outputs in a specific json format or whatever.

I did an experiment where I did very simple SFT on Mistral 7b and it was extremely good at converting receipt images into structured json outputs and I only used 1,000 examples. The difficulty is trying to get a diverse enough set of examples, evaling, etc.

If you have great data with simple input output pairs, you should really give it a shot.

Re: Qwen3.5 Fine-Tuning Guide

#40
post #6

Fine tuning is a story that is nice to tell but that with modern LLMs makes less and less sense. Modern LLMs are so powerful that they are able to few shot learn complicated things, so a strong prompt and augmenting the generation (given the massive context window of Qwen3.5, too) is usually the best option available. There are models for which fine tuning is great, like image models: there with LoRa you can get good…

I think the biggest case for fine tuning is probably that you can take small models, fine tune them for applications that require structured output, and then run cheap inference at scale. "Frontier LLMs can do it with enough context" is not really a strong argument against fine-tuning, because they're expensive to run.

Especially for super constrained applications. I don't care if the language model that I use for my extremely specific business domain can solve PhD math or remember the works of Shakespeare. I'd trade all of that for pure task specific accuracy.
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