Why this repository exists
The upstream finetune was only distributed as BF16 (~55.6 GB) or GGUF. The few
community Int4 quants of it do not load under vLLM:
- two quantize
lm_head to int8, and the XPU mixed-precision kernels implement
only uint4/uint4b8, so engine init dies with
Failed to find a kernel that can implement the WNA16 linear layer ... uint8b128
- one uses
auto-round, which is not a registered quant_method in vLLM
This checkpoint is plain GPTQ, so it loads on stock vLLM (CUDA and Intel XPU) with
no custom patches.
Quantization recipe
Produced with gptqmodel 7.3.2, mirroring the recipe of the already-deployed
Qwen3.8-27B-GPTQ-Int4-sym-G128-MTP-BF16:
Table with columns: setting, value| setting | value |
|---|
| bits | 4 |
| group_size | 64 |
| sym | true |
| desc_act | false |
| true_sequential | true |
| lm_head | false (left unquantized) |
| dynamic | {"-:.*mtp.*": {}} (MTP excluded) |
| pack_dtype | |
Two choices are load-bearing on Intel XPU:
lm_head is left in BF16. There is no int8 weight-only kernel for XPU
(XPUwNa16LinearKernel supports only uint4/uint4b8), so a quantized head
makes the model unloadable.
- Symmetric only. Asymmetric zero-points are likewise unsupported on that path.
lm_head, embed_tokens, linear_attn.in_proj_a, linear_attn.in_proj_b and
the vision tower are all left unquantized; only the 10 Linear projections per
decoder layer are quantized.
Speculative decoding
The MTP draft head is preserved unquantized (15 mtp.* tensors), so
multi-token prediction still works. This is lost in most community quants.
--speculative-config '{"method":"mtp","num_speculative_tokens":4}'
Note this requires the MTP layers to build unquantized. On the patched XPU image
that means leaving lm_head unquantized as above; naive --quantization overrides
can break the draft path.
Evaluation
Perplexity on held-out splits (calibration used TRAIN only; these are TEST),
computed in-process against a live vLLM server so the method is identical across
every model compared:
Table with columns: set, perplexity| set | perplexity |
|---|
| wikitext2 test | 5.272932434355194 |
| gsm8k test | 1.9123032367884933 |
Serving
vllm serve /models/Qwen3.8-27B-TURBO-DF735-882-NM-DAU-GPTQ-Int4-g64-mse \ --quantization gptq \ --dtype float16 \ --max-model-len 100000 \ --kv-cache-dtype fp8 \ --gpu-memory-utilization 0.84 \ --language-model-only \ --enable-auto-tool-choice --tool-call-parser qwen3_xml \ --speculative-config '{"method":"mtp","num_speculative_tokens":4}'
The model natively supports 262144 context; --max-model-len is lowered to fit a
32 GB card alongside the KV cache.
Licenses
- base model
Qwen/Qwen3.8-27B: Apache-2.0
- finetune
DavidAU/Qwen3.8-27B-TURBO-Fable-Cold-Fusion-735-882-Heretic-Uncensored-NM-DAU: Apache-2.0
- this quantization: Apache-2.0, attribution retained as required