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General Q&A · Coding

Qwen3.8-Flash-Next NVFP4

A single-device multimodal inference setup using NVFP4 quantization for Q&A, coding, and agent tasks. Tiered loading from local NVMe keeps the model within unified system memory capacity.

Multimodal understandingText, images, video → text
1 MegaCubeTest report available

01 / Model parameters

Model architecture & capabilities

Qwen3.8-Flash-Next is a multimodal mixture-of-experts model for general Q&A and agent tasks. It uses sparse experts, hybrid attention, and embedding components that support tiered loading, drawing on a subset of compute resources at each step. Total parameters, active parameters per step, and actual device memory use are distinct measures.

  • Local Q&A and content synthesis
  • Code development and debugging
  • Agent tool calling
Publisher / base model
Alibaba Qwen · Qwen3.8-Flash-Next
Parameter breakdown
125B language model / 6B active; an additional 51B N-gram embedding and 4B MTP component
Architecture
48-layer MoE; 512 routed experts, 10 selected per step, plus 1 shared expert; Gated DeltaNet + QSA
Model context
Native 262,144 tokens, expandable to 1M; configured limits and tested lengths listed separately
Input / output
Text, image, and video input; text and tool-call output
Key capabilities
Q&A, complex reasoning, coding, tool calling, and multimodal understanding
Quantization used here
NVIDIA ModelOpt: NVFP4 for main routed experts, BF16 for other main layers, FP8 for MTP experts and PLE
Weight size
Approx. 123.57 GiB / 132.7 GB; not all resident in memory simultaneously
License
NVIDIA Open Model License, with additional Qwen Community terms

Single-device tests here primarily cover low-concurrency text and coding tasks. The public model supports vision; 262K is this service's configuration limit, and full-length stress testing has not been completed.

Model information checked on 2026-09-20

02 / Deployment

MegaCube deployment configuration

Compute devices
1 × MegaCube · NVIDIA GB10 · 128 GB
Engine
vLLM 0.28.1rc1.dev388 · CUDA 13.0 · ARM64
Loading method
PLE local NVMe mmap + staged gather
Validated service settings
TP1;MTP3;seqs=1;chunk=2048;GMU=0.80
Context
Configured limit of 262,144 tokens; Thinking off
  1. Prepare local storage

    Download NVFP4 weights to fast NVMe; tiered PLE reads require local disk storage.

  2. Pinned runtime versions

    Use the vLLM image and rc2 configuration specified in the report, and verify the weights and deployment package.

  3. Start a single-device service

    Default to C1 / MTP3, enable Prefix Cache, and retain the default Compile / Graph settings.

  4. Warm up and connect

    Run health checks and warm up representative tasks, then connect PINVOU to the model service.

Find and download this model in the PINVOU Model Store, then follow its model card to deploy and enable the service.

The Model Store currently offers an rc3 candidate deployment package that has not completed inference acceptance testing on the device. Results on this page come from the earlier rc2 configuration and should be interpreted for that version.

Manage models in PINVOU →
Deployment parameters & versions
Deployment parameters & versions
ParametersRecommended C1 service configurationDescription
Modelnvidia/Qwen3.8-Flash-Next-NVFP4ModelOpt NVFP4 checkpoint, approx. 123.57 GiB / 132.7 GB
Inference enginevLLM 0.28.1rc1.dev388 · CUDA 13.0ARM64 / GB10 environment
Parallelism & schedulingTP1 · max-num-seqs=1 · max-num-batched-tokens=2048Prioritize single-request performance
Context & memorymax-model-len=262144 · GMU=0.80 · KV=auto262K is the configuration limit, not a completed full-length stress test
Speculative decodingMTP=3 · draft vocab=65536Main source of throughput gains
PLELocal NVMe mmap + staged gatherAvoids keeping the entire approx. 50 GiB PLE table resident in unified memory
Compile / GraphDefault VLLM_COMPILE / FULL_AND_PIECEWISEBetter than eager; lower TTFT tail latency than mode0
MoE backendauto → FLASHINFER_CUTLASSAutomatically selected by the current engine
Prefix CacheEnabled by defaultBenefits multi-turn agents, fixed system prompts, and tool definitions
ThinkingDisabled by defaultAll performance results in this report use thinking mode disabled
View commands and configuration references

Before use, set model paths and service addresses for your devices and check the versions and parameters above.

python3 -m pip install -U huggingface_hub
export HF_ENDPOINT=https://hf-mirror.com

hf download nvidia/Qwen3.8-Flash-Next-NVFP4 \
  --local-dir /var/tmp/models/Qwen3.8-Flash-Next-NVFP4-nvidia
docker pull \
  vllm/vllm-openai:nightly-8a728663c1c3eeace834a95f5654fa653cc1998c

# Archived image digest
# sha256:5cba4263b05c258ad4f423f10d83fb7c0da742796471c1b22207642f2733d940
tar -xzf MegaCube-Qwen3.8-Flash-Next-NVFP4-single-1.0.0-rc2.tar.gz
cd megacube-qwen38fn-single
sha256sum -c SHA256SUMS
bash megacube.sh deploy

# Subsequent management
bash megacube.sh start
bash megacube.sh stop
bash megacube.sh status
bash megacube.sh logs
bash megacube.sh smoke-test
bash qwen38fn-c1-balanced.sh

until curl -fsS http://127.0.0.1:8000/health; do
  sleep 10
done
curl -s http://127.0.0.1:8000/v1/models
curl http://MODEL_SERVER_IP:8000/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
    "model":"qwen3.8-flash-next",
    "messages":[{"role":"user","content":"Please write a bubble sort algorithm in C."}],
    "temperature":0,
    "max_tokens":256,
    "stream":true,
    "chat_template_kwargs":{"enable_thinking":false}
  }'

03 / Performance tests

MegaCube performance test results

2026-09-13; 40 questions across eight real-world task types, with three interleaved retest rounds and thinking mode disabled. C1 token generation rates are reported as medians. Prefix caching is tested separately using a shared prefix of approx. 19.9K tokens.

43.70 tok/sC1 · MTP3 · Median token generation rate
0.30 sTTFT P95 for the same real-world workloads
1.486 sMedian TTFT with a stable warm cache for an approx. 19.9K-token prefix
C1: interleaved MTP3 / MTP4 retests
ConfigurationToken generation P50P10TTFT P50/P95Quality scoreMTP acceptance rate
MTP3 · Recommended production setting43.70 tok/s26.900.26 / 0.30 s0.84266.17%
MTP4 · Optional throughput setting46.25 tok/s26.000.27 / 0.32 s0.86057.83%
C2: low-concurrency aggregate throughput (tok/s)
ConfigurationAggregate throughputTTFT P95
MTP348.200.47 s
MTP451.600.53 s
Shared prefix: uncached input and warm-cache runs
StatusTTFTQuery tokensCache-hit tokensHit rateToken generation (tok/s)
Uncached prefix11.579 s19,88400%28.012
First reuse/warm-up11.568 s19,88400%26.475
Warm-cache run 11.509 s19,88417,60088.51%26.792
Warm-cache run 21.483 s19,88417,60088.51%27.675
Warm-cache run 31.486 s19,88417,60088.51%26.537
  • 262K is the service configuration limit; full-length stress testing has not been completed.
  • The first reuse may still miss the cache. A cache hit reduces time to first token; it does not speed up token generation after the first token.
  • Approx. 133 GB of weight files does not mean all weights remain resident in memory simultaneously.

C1 / C4 / C8 denotes 1 / 4 / 8 concurrent requests. TTFT (time to first token) measures elapsed time from submitting a request to receiving its first output token. TPOT (time per output token) measures average time per generated token after the first token. Aggregate throughput is the combined output rate across concurrent requests; a single-request token generation rate is measured separately in tok/s.

Public benchmark references

Model capability & platform performance benchmarks

The following results are published by model developers or platform providers and are separate from the MegaCube tests above. Capability scores measure task performance; tok/s measures token throughput. Results obtained with different models, numerical precision, hardware, or test protocols are not directly comparable.

NVIDIA NVFP4 capability benchmarks

Evaluated model
Qwen3.8-Flash-Next-NVFP4
Test platform
NVIDIA B200 / B300;vLLM
NVIDIA NVFP4 capability benchmarks · Data
BenchmarkScoreWhat it measures
GPQA Diamond91.5Challenging science Q&A
Terminal-Bench 2.182.9Multi-step terminal tasks
MMMU Pro78.3Multidisciplinary multimodal understanding

Test conditionstemperature=1, top_p=0.95, maximum output budget 131,072 tokens, reasoning effort xhigh. See the source for benchmark tool frameworks and task environments; this is not a retest of single-device throughput or accuracy on this page.

View original benchmarks ↗

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