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by michaelt 509 days ago
Personally I've noticed major changes in performance between different quantisations of the same model.

Mistral's large 123B model works well (but slowly) at 4-bit quantisation, but if I knock it down to 2.5-bit quantisation for speed, performance drops to the point where I'm better off with a 70B 4-bit model.

This makes me reluctant to evaluate new models in heavily quantised forms, as you're measuring the quantisation more than the actual model.

2 comments

That's a fair point - the trick with dynamic quants is we selectively choose not to quantize many components - ie attention is left at 4 or 6bit, just the MoE parts are 1.5bit (-1, 0, 1)

There are distilled versions like Qwen 1.5, 3, 14, 32, Llama 8, 70, but those are distilled - if you want to run the original R1, then the quants are currently the only way.

But I agree quants do affect perf - hence the trick for MoEs is to not quantize specific areas!

How are you doing your evals?

Being able to do semantic diffs of the output of the two models should tell you what you need to do.