Gemma 4 QAT models: Optimizing compression for mobile and laptop efficiency

199 pointsposted 6 hours ago
by theanonymousone

58 Comments

simonw

3 hours ago

I just ran one of these locally on a Mac like this:

  uvx litert-lm run \
    --from-huggingface-repo=litert-community/gemma-4-E2B-it-litert-lm \
  gemma-4-E2B-it.litertlm \
    --backend=gpu \
    --prompt="Generate an SVG of a pelican riding a bicycle"
The first time you run that it downloads 3.2GB to ~/.cache/huggingface/hub/models--litert-community--gemma-4-E2B-it-litert-lm

It can handle audio and image input too, which is pretty cool for a 3.2GB model. For images:

  uvx litert-lm run \
    --from-huggingface-repo=litert-community/gemma-4-E2B-it-litert-lm \
  gemma-4-E2B-it.litertlm \
    --backend=gpu --vision-backend gpu \
    --attachment image.jpg --prompt describe
And for audio:

  uvx litert-lm run \
    --from-huggingface-repo=litert-community/gemma-4-E2B-it-litert-lm \
  gemma-4-E2B-it.litertlm \
    --backend=gpu --audio-backend cpu \
    --attachment audio.wav --prompt transcribe
(The pelican is rubbish, but it's only a 3.2GB file so the fact it even outputs valid SVG is impressive to me: https://gist.github.com/simonw/94b318afde4b1ce5ff67d4b5d0362... )

reactordev

an hour ago

Not to mention the text-only 0.8GB version. Just crazy. You can have basic real-time conversations on-device that's video and audio aware now.

simonw

17 minutes ago

Have you seen a 0.8GB model file floating around yet? I couldn't find one earlier.

jhatax

5 minutes ago

It’s the Friday before WWDC during which Apple is going to announce an “improved” Siri based on Google models (a locked partnership, for now). Maybe it’s a coincidence, but this might be Google releasing models that will be showcased next week by Apple?

No knowledge, just speculation.

satvikpendem

4 hours ago

Unsloth's collection as well [0], with their results [1]. Looks like they can get very close to 100% accuracy compared to the BF16 model that is unquantized, and Unsloth's quants are better than the original Google's QAT as posted in the article.

Personal I'm using the 2B model for web search and structured JSON output back via Unsloth Studio and its API, works very well for that even with the model embedded on phones.

[0] https://huggingface.co/collections/unsloth/gemma-4-qat

[1] https://unsloth.ai/docs/models/gemma-4/qat#qat-analysis

llmoorator

4 hours ago

you misunderstand what that chart shows - it shows BF16 QAT Q4_0, not BF16 regular.

meaning Google quantized the model to 4 bit and stored the result in BF16 format for compatibility and convenience to downstream packers.

Like storing small 8 bit numbers in full 32 bit integers.

So it's not close to 100% of unquantized BF16.

I'm curious if anybody can explain why Google released 4 bit QAT Q4_0 is not exactly 100% of BF16 QAT Q4_0? seems like it should be just bit twiddling, no further quantization to convert between these two packings. Unsloth talks about "lattice alignment" being an issue.

That being said I hate it that smol model makers, like Google, Qwen, ... only show the BF16 benchmarks when they release a new models, knowing that what people really run are 4-8 bit quantizations, so it's really hard to understand how much you lose when you run 4 bit vs 6 bit...

coder543

2 hours ago

> meaning Google quantized the model to 4 bit and stored the result in BF16 format for compatibility and convenience to downstream packers.

You also misunderstand what is happening. Google did not do that. Google further trained the original model with an objective of minimizing error when quantized to 4-bit. The BF16 QAT is not an upscaled 4-bit model. When quantized to 4-bit, it should lose less accuracy than a typical 16-bit model loses when quantized to 4-bit, but the loss is not zero, because it is not based on a 4-bit model.

The Gemma 3 QAT report was a bit clearer:

https://developers.googleblog.com/en/gemma-3-quantized-aware...

"Instead of just quantizing the model after it's fully trained, QAT incorporates the quantization process during training. QAT simulates low-precision operations during training to allow quantization with less degradation afterwards for smaller, faster models while maintaining accuracy. Diving deeper, we applied QAT on ~5,000 steps using probabilities from the non-quantized checkpoint as targets. We reduce the perplexity drop by 54% (using llama.cpp perplexity evaluation) when quantizing down to Q4_0."

The BF16 is just trained to be more resistant to simulated quantization, which helps when it is actually quantized. Google is not doing post-training on the 4-bit model directly.

satvikpendem

3 hours ago

Ah I see, thanks for the clarification.

slopinthebag

4 hours ago

I'm confused, the unsloth model is ~600mb and the one from google is 7gb?

overfeed

2 hours ago

One is quantized, the other one is Quantization-ready.

jbarrow

an hour ago

Very impressed with how much the Gemma ecosystem has advanced just this week.

Gemma 12B, multitoken prediction, and official quants released. Feels like Google is putting real effort into this string of releases, and I'm very excited to see that!

minimaxir

5 hours ago

It's a bit awkward to release Gemma 4 12B (https://news.ycombinator.com/item?id=48385906), and then a canonical Q4_0 Gemma 4 12B a couple days later.

It's good that this post lists the expected VRAM usage for the models with Q4_0 Gemma 4 12B being 6.7GB, which will indeed fit Google's claims of fitting within 16GB comfortably, altough it confirms that only the quantized version will do so.

Relatedly, in Google's newly released Edge Gallery for macOS, Gemma 4 12B is explicitly listed as unsupported due to not enough RAM even on a 16GB machine, but given the expected VRAM usage here the Q4_0 variant definitely should fit and Google should fix that.

Aurornis

4 hours ago

I'm not sure why you think it's awkward to have multiple releases. It's better to release models and variations as they're ready, not withhold them all until everything is ready to release all at once.

The Q4_0 is a quantization aware training checkpoint. It's not a simple quantization of the original Gemma 4 12B.

netdur

5 hours ago

not sure if I understand you, but 4Q and QAT 4Q are different

refulgentis

4 hours ago

It's super annoying when you have products that utilize these because there's...4? releases in 3 weeks?

- Gemma 4 2B/4B/27BE3B/31B

- Gemma 4 2B/4B/27BE3B/31B x "assistant" / MTP drafter models (i.e. multitoken prediction)

- Gemma 4 12B (2 days ago? 1?)

- Gemma 4 QAT 2B/4B/12B/27BE3B/31B x "assistant" models (i.e. multitoken prediction)

It probably sounds silly and really whiny in the abstract. It just causes a ton of work / confusion downstream that feels unnecessary.

Extremely glad for the output, not glad to have to chase it.

ex. llama.cpp currently supports the originals but not the MTP predictors but there is a patch for the MTP predictors but not for the small MoE models and I think it supports the 12B but maybe not media for it yet and now we have these too and the blog says there's GGUFs (llama.cpp models) but there isn't in any of the 12? repos I clicked through. and ~every consumer-facing local LLM app is built on llama.cpp or a fork of it.

Also if anyone at Google is taking feedback over to b/ or product, pleaseeee stop the "E"2B "E"4B thing, unless it's actually taking up less RAM on Android during CPU inference. I can't tell if I need to treat the 4B like an 8B (i.e. beyond most consumer hardware without a GPU) or a 4B (i.e. will run on most consumer hardware since 2021)

EDIT: And, yes, the QAT 12B x mmproj does not work with llama.cpp. I'm glad there's people who have the luxury of not having to, well, actually use these and treat me as whining :) I'll need to schedule another 4-8 hours of work for the 4th time, no fun!

ddarolfi

4 hours ago

These models aren't products? They are open source ish (open weight I guess), research outputs. While the naming scheme may be confusing, it is relevant and important. I believe it's on you to understand it.

refulgentis

4 hours ago

I understand it. :)

And you're absolutely right to point out they aren't products - I hoped that was clear - when you're building a product with them, you end up having to do the same build loop 4 times, in this instance :)

overfeed

2 hours ago

You can stop after the first one. Choosing to repeat the process is on you, and probably because you see some benefit in using the variant(s) you build on top of.

ddarolfi

2 hours ago

Yes my framing was a little confusing. You were clear in that you are building products on them. I was more saying that because these gemma models are not products, and instead research outputs, the naming scheme should be more scientific rather than consumer friendly.

satvikpendem

4 hours ago

Just use Unsloth Studio it supports them all.

netdur

5 hours ago

had a good run with Gemma 4 E2B Unsloth 4Q: https://youtube.com/shorts/XLsAnz5aAAI

The E4B model doesn’t fit on my phone TPU, so it swaps to RAM, the QAT version means more accuracy, good!

prism56

an hour ago

How do you know it swaps to ram vs on the TPU?

Would be interested in testing this on my pixel.

Catloafdev

an hour ago

Being able to run the 12B on 8gb VRAM is huge. It's crazy to see how fast these small local models have evolved.

somewhatrandom9

4 hours ago

Could these quantized models make MTP (Multi-Token Prediction) significantly faster when used as drafters for larger regular Gemma 4 models?

dist-epoch

3 hours ago

Google already released specialized drafters for Gemma 4.

cr3cr3

4 hours ago

For a moment I got excited thinking QAT is Intel Quick Assist Technology...

razighter777

2 hours ago

Same I had to do a double take. Would be pretty humourous if they somehow took advantage of crypto offloading to accelerate ai inference

zkmon

3 hours ago

How can the smaller Unsloth GGUF quant can beat the original google quant? (ref: unsloth/gemma-4-31B-it-qat-GGUF)

redox99

3 hours ago

I was just testing Gemma E2B and E4B yesterday, and they are just too dumb to be useful outside of niche use cases.

Besides, there's no good agent on Android. Having a model that can't run web searches and browse websites is limited in use, particularly small models that really need to be grounded on search results to be factual, because they can't memorize enough.

Edit: I'd like to know what kind of usage the people that seem to disagree and downvoted this are having.

ilaksh

2 hours ago

I think that's probably true for the vast majority of Android phones. But if you have a SOTA expensive beast, I wonder if Gemma 4 12B at 4 bit could work? Maybe something like a Redmagic 11 pro or OnePlus 13 running NanoClaw?

But also maybe a few Qwen 3.6 or Qwen 3.5 variants can fit and can handle some simple tasks.

redox99

an hour ago

I think Gemma 4 12B is definitely possible to run on high end phones, google claims you need 16GB of memory. But it's probably not very usable, you'll need to swap most stuff other than the LLM.

When I tried E2B and E4B with Google Edge Gallery, and added a web search skill from the skill list, E2B would fail (get stuck in a loop), E4B would need a very specific instruction, "weather in [city name]" would not call the web search tool, I'd need "web search weather in [city name]". And the result was completely hallucinated and impossible. It claimed 14c and feels like 4c (which is impossible), and 10% humidity (which is almost impossible in this city)

Asking wikipedia level history questions (without any tool use), the results were awful as well.

satvikpendem

32 minutes ago

I'm running a service in production using Gemma 4 models, to get structured JSON output back from web search tool calls using Unsloth Studio and its API, but it did require a rather large and detailed system prompt and tool call healing if the format wasn't JSON for example (retries, reprompting with feeding the error back into the model, etc, this is also what Unsloth Studio does for its self-healing tool call feature). But once I did that, it's been working quite well and on benchmarks I've made, it's about 97% accurate after the first time and basically 100% accurate after retries.

This is running on a server though, not sure how well it'd work on a phone, I should try that. I used AI Edge Gallery on Android and it doesn't seem too good at the web search tool but maybe the web search tool itself, being a community made tool, is pretty bad, because tool calling via Unsloth Studio seems to work just fine with the exact same Gemma models on desktop/server vs the phone.

redox99

17 minutes ago

I agree that the web search tool probably is pretty bad. However a smart model would never hallucinate impossible weather data if the search tool failed.

I'm sure you can get some out of it if you babysit it with an optimized prompt, harness, etc and you can tolerate some failures. But when I try to run the ChatGPT prompts from my history, even if I pick the easier ones, it's hopeless.

I'd like to have a local agent on the phone with wikipedia level knowledge. But you probably need more like 30B params.

steno132

an hour ago

I don't get this obsession with smaller models. I've been using Claude and GPT models for years and have had zero issues with them.

I see absolutely no benefit to me as a end user for a local model which is going to take up more of my CPU and memory and slow down my machine. I almost always have Internet and if I don't then not having access to a AI model is the least of my concerns.

adam_arthur

an hour ago

The entire universe of automation projects that can be run effectively for free relative to SoTA models?

I don't think many realize that most LLM embedded automation, pipelines, products will soon be able to run extremely cheaply on models < 100B parameters.

Frontier models will be used for coding/creation use cases, yes. But for all the pseudo-deterministic, pipeline, analysis style things there will be no practical benefit to running frontier models, only additional cost.

Gemma 4 26B outperforms most 100-200B models that I've tested for reasoning and structured output.

Gemma 4 12B can consistently select where to click on browser images given a minimal prompt, and do so very quickly.

dofm

an hour ago

The 26B model is really surprising, and it is impressively concise — it spends a lot less time dithering than Qwen3.6.

steno132

an hour ago

Practically if you're running a small personal automation project you're not going to want to waste a lot of time configuring and tuning a local model. You want to build the automation and move on.

If you're building a automation as a company you definitely won't want to take on the long term maintenance overhead of running your own models for some automation project.

adam_arthur

an hour ago

These small models exist in the cloud and are/will be priced commensurately to their size.

Your claim is effectively that companies don't care about operational/cloud costs. Even pre-LLM, companies regularly assessed and tried to pare down cloud spend.

mikeocool

an hour ago

> I've been using Claude and GPT models for years

All 3 years?

steno132

an hour ago

GPT1 was released in 2018, so yes, since then.

user2722

an hour ago

There is tinfoil.sh as well but honestly running this stuff on an airgapped server allows a better peace of mind about the data being used for something else.

steno132

an hour ago

What's wrong with the data being used for something else? Someone is providing digital intelligence to us, saving us many hours a week, so the least we can do is provide them a little data so they are able to improve their service.

It would be selfish and unethical not to in my view. And ultimately the data is just being used in order to improve the models and benefit us, not for anything nefarious.

Zambyte

an hour ago

I like using my computer.

steno132

an hour ago

Exactly, thank you, we are on the same page! It's great to be able to use our own devices and not have their compute coopted by a third party.

I'd rather not have intensive compute needed shifted onto my personal machine which I want to use for something else.

Zambyte

an hour ago

I am not a "third party" on my own computer.

satvikpendem

an hour ago

By that logic, any software you run that isn't fully built by yourself is "third party" therefore you shouldn't run anything at all on your machine, thus obviating the need for it entirely.

steno132

an hour ago

But practically AI inference requires substantial local computing resources. It's not some web app, it's a order of magnitude more compute needed

Zambyte

36 minutes ago

Hopefully now you understand why people want smaller models.

satvikpendem

30 minutes ago

Not really, I run a production service on a basic server using these Gemma models, the server is weaker than my MacBook. Most people's laptops and even phones actually can run local models, most simply don't know how. Run Unsloth Studio and you'll see how easy it is.

As the sibling says this is why people want smaller but still performant models.

mannanj

an hour ago

I don't like the gaslighting of paying Anthropic or Open(Closed)AI and it being said its unsustainable for them to take my payment while simultaneously they take my data (edit: which is incredibly valuable) and I cannot opt out of that.

The obsession is for leaving hostile and abusive entities, the corporations or the people who fund them that have a horrible track record in regards to ethicality, rights and respect & human dignity.

steno132

an hour ago

My view is, if you're going to use the service - you should give the data.

It's like using Gmail and expecting them not to train their AI models on your data - how can you expect that when they're giving you a secure, reliable, highly functional email client completely for free?

The digital economy only works if everyone pays their fair share. If you don't want to give your data then you are really harming everyone by slowing down AI development for everyone else.

klardotsh

an hour ago

Because we pay for the models.

If I pay you for a service, what implicit right should you have to then continue to profit in perpetuity by storing the data I paid you to process?

If LLMs were free your Gmail analogy might hold up. They aren’t, and so it doesn’t.

AI development can continue with the data folks opt into, or with the data AI companies incessantly scrape with reckless disregard for polite system loads. AI development does not require retaining all user inputs forever.