No — not on this device
Qwen3.5 397B-A17B at Q4_K_M needs 227.4 GB against 18.0 GB usable, and the shortfall of 209.4 GB is more than 16 GB of system RAM can cover at a tolerable speed. A smaller sibling or a lower quantisation is the honest answer here.
Flagship-class at 17B active. A 256 GB Mac Studio or a multi-GPU box at Q4.
What hardware do I need for Qwen3.5 397B-A17B? →
Fits instead: Qwen3.5 9B (6.3 GB) · Qwen3.5 4B (3.5 GB)
The VRAM budget
Quantisation ladder
| Quant | Weights | Total @ 8K | Max context | Tok/s | Quality | Fit |
|---|---|---|---|---|---|---|
| Q8_0 | 398.8 GB | 399.6 GB | — | ~1.6 | −0.1% ppl | 381.6 GB over |
| Q6_K | 307.8 GB | 308.6 GB | — | ~2.0 | −0.4% ppl | 290.6 GB over |
| Q5_K_M | 266.0 GB | 266.8 GB | — | ~2.3 | −0.8% ppl | 248.8 GB over |
| Q4_K_M | 226.6 GB | 227.4 GB | — | ~2.7 | −1.9% ppl | 209.4 GB over |
| Q3_K_M | 183.4 GB | 184.3 GB | — | ~3.4 | −5.4% ppl | 166.3 GB over |
| Q2_K | 157.2 GB | 158.0 GB | — | ~3.9 | −15% ppl | 140.0 GB over |
Quality is the published perplexity delta against f16 weights. Max context assumes an f16 KV cache; q8_0 roughly doubles it. Only 15 of its 60 blocks keep a per-token KV cache; the rest are linear-attention, Mamba or convolution blocks with a fixed-size state.
How to run it
$ pip install mlx-lm $ mlx_lm.generate --model mlx-community/Qwen3.5-397B-A17B-4bit \ --max-tokens 512 --prompt "Hello"
Apple's own array framework. The fastest path on Apple Silicon. More on MLX.