You don’t know which expert you’ll need for each layer, so you either keep them all loaded in memory or stream them from disk
That said, it is possible to train a model in a quantization-aware way[2][3], which improves the quality a bit, although not higher than the raw model.
Also, a loss in quality may not be perceptible in a specific use-case. Famously LMArena.ai tested Llama 3.1 405B with bf16 and fp8, and the latter was only 2 Elo points below, well within measurement error.
[0]: https://github.com/ggml-org/llama.cpp/blob/master/examples/q...
[1]: https://github.com/ggml-org/llama.cpp/discussions/5063#discu...
But if you don't already know the question your asking is not at all something I could distill down into a sentence or to that would make sense to a lay-person. Even then I know I couldn't distill it at all sorry.
Edit: I found this link I referenced above on quantized models by bartowski on huggingface https://huggingface.co/bartowski/Qwen2.5-Coder-14B-GGUF#whic...
For bigger models (in range of 8B - 70B) the Q4KM is very good, there are no any degradation compared to full FP16 models.
Yes.
The reason: MoE. They are able to run at a good speed because they don't load all of the weights into the GPU cores.
For instance, DeepSeek R1 uses 404 GB in Q4 quantization[0], containing 256 experts of which 8 are routed to[1] (very roughly 13 GB per forward pass). With a memory bandwidth of 800 GB/s[3], the Mac Studio will be able to output 800/13 = 62 tokens per second.
[0]: https://ollama.com/library/deepseek-r1
[1]: https://arxiv.org/pdf/2412.19437
[2]: https://www.apple.com/newsroom/2025/03/apple-unveils-new-mac...