Gemma 3 QAT Models: Bringing AI to Consumer GPUs

I think gemma-3-27b-it-qat-4bit is my new favorite local model - or at least it's right up there with Mistral Small 3.1 24B.

I've been trying it on an M2 64GB via both Ollama and MLX. It's very, very good, and it only uses ~22Gb (via Ollama) or ~15GB (MLX) leaving plenty of memory for running other apps.

Some notes here: https://simonwillison.net/2025/Apr/19/gemma-3-qat-models/

Last night I had it write me a complete plugin for my LLM tool like this:

  llm install llm-mlx
  llm mlx download-model mlx-community/gemma-3-27b-it-qat-4bit

  llm -m mlx-community/gemma-3-27b-it-qat-4bit \
    -f https://raw.githubusercontent.com/simonw/llm-hacker-news/refs/heads/main/llm_hacker_news.py \
    -f https://raw.githubusercontent.com/simonw/tools/refs/heads/main/github-issue-to-markdown.html \
    -s 'Write a new fragments plugin in Python that registers
    issue:org/repo/123 which fetches that issue
        number from the specified github repo and uses the same
        markdown logic as the HTML page to turn that into a
        fragment'

It gave a solid response! https://gist.github.com/simonw/feccff6ce3254556b848c27333f52... - more notes here: https://simonwillison.net/2025/Apr/20/llm-fragments-github/

Can you quote tps?

More and more I start to realize that cost saving is a small problem for local LLMs. If it is too slow, it becomes unusable, so much that you might as well use public LLM endpoints. Unless you really care about getting things done locally without sending information to another server.

With OpenAI API/ChatGPT, I get response much faster than I can read, and for simple question, it means I just need a glimpse of the response, copy & paste and get things done. Whereas on local LLM, I watch it painstakingly prints preambles that I don't care about, and get what I actually need after 20 seconds (on a fast GPU).

And I am not yet talking about context window etc.

I have been researching about how people integrate local LLMs in their workflows. My finding is that most people play with it for a short time and that's about it, and most people are much better off spending money on OpenAI credits (which can last a very long time with typical usage) than getting a beefed up Mac Studio or building a machine with 4090.

> Whereas on local LLM, I watch it painstakingly prints preambles that I don't care about, and get what I actually need after 20 seconds.

You may need to "right-size" the models you use to match your hardware, model, and TPS expectations, which may involve using a smaller version of the model with faster TPS, upgrading your jardware, or paying for hosted models.

Alternatively, if you can use agentic workflows or tools like Aider, you don't have to watch the model work slowly with large modles locally. Instead you queue work for it, go to sleep, or eat, or do other work, and then much later look over the Pull Requests whenever it completes them.

I have a 4070 super for gaming, and used it to play with LLM a few times. It is by no means a bad card, but I realize that unless I want to get 4090 or new Macs that I don't have any other use for, I can only use it to run smaller models. However, most smaller models aren't satisfactory and are still slower than hosted LLMs. I haven't found a model that I am happy with for my hardware.

Regarding agentic workflows -- sounds nice but I am too scared to try it out, based on my experience with standard LLMs like GPT or Claude for writing code. Small snippets or filling in missing unit tests, fine, anything more complicated? Has been a disaster for me.