Qwen3.8-27B-NVFP4-FTW

Qwen3.8-27B NVFP4 — SparkLab FTW

This is an experimental, text-only SparkLab FTW checkpoint for Qwen3.8-27B on one NVIDIA DGX Spark with 128 GB coherent unified memory.

SparkLab provides a GB10-native inference engine, model recipes, hardware checks, memory planning, artifact preparation, and OpenAI-/Anthropic-compatible serving APIs.

What this repository contains

This repository does not introduce a newly trained model or a new quantization. It repackages Inferact/Qwen3.8-27B-NVFP4 into the native FreeToken Weight (FTW) layout used by SparkLab.

• Base model: Qwen/Qwen3.8-27B, a dense 27B model.
• Quantized source revision: 6128240ebaf4eaa7bad2b3d1c72c37d677c5f462.
• FTW fingerprint: af78f7411817bb73.
• Three FTW weight shards, totaling 24,617,562,112 bytes (24.62 GB).
• freetoken_weight.json, configuration, tokenizer, chat template, generation settings, and upstream license.

The conversion prepares the published ModelOpt NVFP4 weights for the native loader; non-quantized tensors remain in their runtime conversion layout. No additional model training is performed. This is a text-model artifact, not a standard Transformers/vLLM safetensors checkpoint. Inherited processor metadata does not enable images or video in SparkLab.

The optional DFlash2 draft is not included. Download it separately as described below; its weights and license belong to its own repository.

Why use FTW?

FTW performs tensor-layout preparation ahead of time for reproducible native loading. This dense model runs resident in unified memory; it does not require NVMe expert offloading. FTW by itself is not a claim of increased model quality or faster steady-state generation.

Run with SparkLab on NVIDIA DGX Spark

Use ARM64 Linux / DGX OS, GB10/SM121, CUDA 13, and local NVMe. A current source installation is recommended, especially for the optimized DFlash2 path.

git clone https://github.com/sixteen-miles-labs/sparklab.git
cd sparklab
uv venv && source .venv/bin/activate
uv pip install -e ".[accel]"

hf download oakmindai/Qwen3.8-27B-NVFP4-FTW \
  --local-dir /path/to/models/Qwen3.8-27B-NVFP4-FTW

sparklab doctor --storage-path /path/to/models
sparklab serve \
  --model /path/to/models/Qwen3.8-27B-NVFP4-FTW \
  --nvfp4-backend triton \
  --cache-type radix --page-size 16 \
  --cuda-graph-max-bs 1 --max-running-requests 1 \
  --num-tokens 65536 --max-seq-len-override 65536 \
  --host 127.0.0.1 --port 1919

Replace /path/to/models with your local model directory. These instructions download the prebuilt target directly; the current catalog recipe may still prepare it from Inferact rather than download this Hub repository.

Once ready, check the model ID and send a request:

curl http://127.0.0.1:1919/health
curl http://127.0.0.1:1919/v1/models
curl http://127.0.0.1:1919/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{"model":"Qwen3.8-27B-NVFP4-FTW","messages":[{"role":"user","content":"Hello!"}],"temperature":0,"max_tokens":128,"stream":true}'

Optional DFlash2 single-stream profile

Download the pinned draft:

hf download maurienne-ai/Qwen3.8-27B-DFlash2-NVFP4-RTNcal \
  --revision bd7a934213c47a9e7ef69eef36bb3325f47fd1f1 \
  --local-dir /path/to/models/qwen3.8-27b-dflash2

Instead of the target-only server, launch the measured 16K-capacity configuration:

sparklab serve \
  --model /path/to/models/Qwen3.8-27B-NVFP4-FTW \
  --nvfp4-backend triton --attention-backend triton \
  --cache-type radix --page-size 16 \
  --cuda-graph-max-bs 1 --max-running-requests 1 \
  --num-tokens 16384 --max-seq-len-override 16384 \
  --speculative-method dflash2 --speculative-tokens 12 \
  --speculative-draft-model /path/to/models/qwen3.8-27b-dflash2 \
  --host 127.0.0.1 --port 1919

Performance and validation limits

All numbers below are single-stream, not aggregate concurrent throughput.

The DFlash2 result is a three-trial median and reproduced the original target-only output on that short probe. Against a fresh matched DFlash2-8 control (37.69 tok/s), the improvement was 21.7%. A separate 512-token, thinking-off sweep measured 59.58 tok/s for math, 37.51 for coding, and 19.26 for prose. These are individual workloads, not general task-suite averages. Full longer traces can differ due to floating-point rounding from verification grouping.

See DFlash2 evidence and target-only evidence.

• Target-only exact 65,536-token recall and reasoning/tool/coding probes passed.
• The declared upstream 262K context has not been validated on this GB10 path.
• DFlash2 is opt-in and batch-one greedy; 64K speculative context, sampling, concurrency, and endurance certification remain outstanding.
• Short output parity does not establish broad quality equivalence. Full Fast-tier certification, including a clean-revision 60-minute endurance run, remains pending.
• This upload reuses the previously tested artifact; it is not a new GPU benchmark.

See the SparkLab model guide for current instructions and limitations.

Credits and license

• Model architecture and base weights: Qwen.
• Published NVFP4 checkpoint: Inferact, using the ModelOpt format.
• Quantization tooling: NVIDIA Model Optimizer.
• Native inference, conversion, GB10 optimization, and deployment: SparkLab.
• Original FTW format and upstream runtime foundations: FreeToken; see SparkLab's NOTICE.
• FTW publishing: OakMind AI.
• Optional external draft: maurienne-ai.

The pinned source declares Apache License 2.0; its LICENSE is included unchanged. Refer to the source model card and Qwen documentation for upstream model information, limitations, and intended-use guidance. Upstream multimodal results are not SparkLab deployment certification. Evaluate generated answers for correctness and suitability for your application.