spicyneuron/Kimi-K2.6-MLX-3.3bit

Kimi K2.6 optimized to run comfortably on a Mac Studio M3 512. This is the smaller, compact version. Quality-first version here.

• A mixed-precision quant that balances speed, memory, and accuracy.
• 3-bit baseline with important layers at 8-bit and BF16.
• Fits into ~430 GB memory, leaving plenty of room to run a smaller, faster utility model (ex: Qwen 3.6 35B, Gemma 4 26B).
• This quant does not support image input.

Usage

# Start server at http://localhost:8080/v1/chat/completions
# Kimi K2.6 requires tiktoken + remote code for the tokenizer
uvx --from mlx-lm --with tiktoken \
  mlx_lm.server \
    --host 127.0.0.1 \
    --port 8080 \
    --trust-remote-code \
    --model spicyneuron/Kimi-K2.6-MLX-3.3bit

Benchmarks

metric	3.6 bit	3.3 bit (this model)
bpw	3.578	3.331
peak memory (1024/512)	460.444	428.735
prompt tok/s (1024)	221.704 ± 0.057	223.613 ± 0.098
gen tok/s (512)	21.095 ± 0.070	21.363 ± 0.035
kl mean	0.022 ± 0.001	0.051 ± 0.002
kl p95	0.053 ± 0.001	0.113 ± 0.002
perplexity	3.559 ± 0.021	3.550 ± 0.020
hellaswag	0.594 ± 0.022	0.590 ± 0.022
piqa	0.848 ± 0.016	0.852 ± 0.016
winogrande	0.670 ± 0.021	0.690 ± 0.021

Tested on a Mac Studio M3 Ultra with:

mlx_lm.kld --baseline-model path/to/mlx-full-precision
mlx_lm.perplexity --sequence-length 512 --seed 123
mlx_lm.benchmark --prompt-tokens 1024 --generation-tokens 512 --num-trials 5
mlx_lm.evaluate --tasks hellaswag --seed 123 --num-shots 0 --limit 500
mlx_lm.evaluate --tasks piqa --seed 123 --num-shots 0 --limit 500
mlx_lm.evaluate --tasks winogrande --seed 123 --num-shots 0 --limit 500

Note:

• mlx_lm.kld is approximate, based on top_k not full logits. Here's the code.
• Kimi K2.6 KL divergence calculated against the largest quant I could run locally (~490 GB), so real KL is higher.

Methodology

Quantized with a mlx-lm fork, drawing inspiration from Unsloth/AesSedai/ubergarm style mixed-precision GGUFs. MLX quantization options differ from llama.cpp, but the principles are the same:

• Sensitive layers like MoE routing, attention, and output embeddings get higher precision
• More tolerant layers like MoE experts get lower precision