Z-Image-Engineer-V6 DFlash draft (b16)

A DFlash block-diffusion draft head for Z-Image-Engineer V6 with the Master Style prompt-rewrite LoRA attached (pottokao/zeng-v6_master-pe_lora_v4.1-r32-ep2_20260928), i.e. the Master Style role-play system prompt + style card workload on the rewrite (PE) role of the ComfyUI-DualHead-Dragon node. Started from z-lab/Qwen3-4B-DFlash-b16; same architecture and tensor names (5 layers, block 16, target layers 1/9/17/25/33).

It is specialised: it only speeds up that workload. On other prompts it still gives correct output (speculative decoding never changes what the target produces) but guesses less often.

Files

file MB use
model.safetensors + config.json + dflash.pyโ€ฆ 1075 z-lab / transformers / vLLM format
gguf/z-image-engineer-v6-dflash-b16-bf16.gguf 1081 llama.cpp reference
gguf/z-image-engineer-v6-dflash-b16-Q8_0.gguf 577 near-lossless
gguf/z-image-engineer-v6-dflash-b16-Q6_K.gguf 447 recommended
gguf/z-image-engineer-v6-dflash-b16-Q4_K_M.gguf 323 smallest; same speed as Q6_K

The GGUFs were converted with convert_hf_to_gguf.py --target-model-dir <V6 HF> and quantized with llama-quantize from the bf16 file. The draft shares the target's token embedding and output head, so the files hold only the 5 draft layers.

llama-server -m <V6 gguf> --lora <master PE LoRA gguf> -md gguf/z-image-engineer-v6-dflash-b16-Q6_K.gguf \
  --spec-type draft-dflash --spec-draft-n-max 15 -fa on -np 1

Single sequence only: upstream draft-dflash acceptance collapses with many parallel sequences (llama.cpp #27117). --spec-draft-n-max 15: llama.cpp verifies 9โ€“16 tokens at almost the cost of one, 5โ€“8 is the expensive range.

Results

Offline, 120 held-out prompts, K=15:

z-lab original this head
tau (tokens advanced per verify, incl. bonus) 2.096 3.977
position 1..8 accuracy .58 .40 .29 .22 .18 .15 .14 .12 .78 .65 .54 .46 .40 .35 .31 .28

llama.cpp (native draft-dflash, K=15), target V6 DHQ 2.9 GB + master PE LoRA v4.1 (f16), 10 Master Style prompts with different cards, greedy, 1000 new tokens max, one RTX 5060 Ti 16 GB:

draft tok/s speed-up acceptance
none 87.0 1.00ร— -
bf16 151.5 1.74ร— 16.8%
Q8_0 159.3 1.83ร— 16.7%
Q6_K 161.2 1.85ร— 16.7%
Q4_K_M 162.4 1.87ร— 16.6%

bf16 / Q8_0 / Q6_K give identical outputs on all 10 prompts, Q4_K_M on 9 of 10 (one greedy near-tie). With the LoRA merged into the target instead of attached at runtime: 107.4 โ†’ 209.0 tok/s (Q6_K draft, 2.40ร— over the LoRA-attached baseline).

Training

  • Data: 9,072 Master Style prompts regenerated with V6 + the master PE LoRA (v4) (vLLM, temp 0.7 / top_p 0.8 / top_k 20, thinking off); 326 held out.
  • Target features: V6 bf16 with the LoRA merged. anchors 128 / 2 epochs / lr 1e-4 cosine / 4 seqs per step / position-decay gamma 7 / 8-bit AdamW; 4,532 steps (train_dflash_v6.py, 2x RTX 5060 Ti, 4.56 s/step).

sha256

  • model.safetensors 52bee0ee736c70a3f672e7ab741606ae453b5fd74d607cd1dcd1dbcfad47ccb4
  • bf16 gguf d9a7aac5af73d7047751a7b3a40cdde6e9ce9d69cd5f7a8a4f61d4f70175cd9b
  • Q8_0 gguf 3b66ee8e7b29eeca3452ce57b6f1080f498332c5f5c990a08ae1e4d19d460cba
  • Q6_K gguf 251ffb5b431f3eb3af7a02721e5f544365ceebb39ca1a82ba9019b5a688072c2
  • Q4_K_M gguf 2a35df57a79be2f6a8c883d691f8581b61aa2ed994a191a84bc60514855ba7a8

License

CC BY-NC 4.0 (non-commercial, free); commercial use needs a separate license from the author. It covers only these weights: the base model and the image models (DiTs) keep their own licenses. Details and upstream notices: LICENSE.md.

Downloads last month
672
Safetensors
Model size
0.5B params
Tensor type
BF16
ยท
Inference Providers NEW
This model isn't deployed by any Inference Provider. ๐Ÿ™‹ Ask for provider support

Model tree for pottokao/Z-Image-Engineer-V6-DFlash-b16

Quantized
(4)
this model