Comment by verdverm
7 days ago
4bits is a cutoff point for many model families, but also depends on what parts you quant to 4bits vs alternatives (weights, weight+activation, kv cache). Also depends on model size and task, lots of nuance in quanting I've come to learn.
Good evaluation from 2024 https://arxiv.org/pdf/2402.18158
I'm currently working towards an updated version (not an og author), curious if others are aware of similar surveys, as I have yet to do a real lit search.
The key point here, I think, is not the 4-bit but the QAT — the model is trained with the objective of losing the least at 4-bit quantiZation (I am assuming it is literally about assigning numbers that quantize better).
The 12B QAT model is indeed sort of mindblowing.
Gemma 4 12B QAT is amazing - agents run very fast, and it's really very smart, at least in my agent's harness domain which is GNU software development - on par with frontiers like GPT Sol, DeepSeek, or Claude - Why to buy those expensive tokens if a local tiny model performs so well?
What's your harness setup? I haven't had this kind of on-par success with any local LLM yet.
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I haven't dug into QAT deeply, better recovery is my understanding as well, and also that it is out of reach for most people because you have to train a model to back prop errors based on estimated error under quant.
Hopefully more of the lab releases are trained under QAT so we can all benefit.
I think they did Gemma 3 QAT models and there are QAT versions of essentially all the Gemma 4 models (including DiffusionGemma).