Qwen3.8-Flash-Next Quark MXFP4 + FP8

Mixed-precision derivative of amd/Qwen3.8-Flash-Next-Quark-MXFP4.

The AMD Quark checkpoint is retained as the base: language-model routed and shared MoE experts remain in OCP MXFP4, while additional high-memory BF16 components are converted to FP8 using precision/layout choices cross-checked against the official Qwen/Qwen3.8-Flash-Next-FP8 and nvidia/Qwen3.8-Flash-Next-NVFP4 checkpoints.

The objective is straightforward: reduce the remaining BF16 footprint while preserving the behavior of the high-quality AMD MXFP4 checkpoint.

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Quantization Layout

The source AMD checkpoint already provides:

  • OCP MXFP4 static weights for language-model routed MoE experts
  • OCP MXFP4 static weights for the shared MoE expert
  • Dynamic MXFP4 expert activations
  • BF16 attention, PLE, MTP, router/gating paths, vision tower, hyper-connections, and lm_head

This derivative additionally converts:

Component Source This model
Main routed/shared MoE experts OCP MXFP4 OCP MXFP4, preserved
PLE n-gram embedding BF16 FP8 E4M3FN
MTP routed expert projections BF16 Quark FP8, 128×128 block
Attention / linear attention BF16 BF16
Router and shared-expert gates BF16 BF16
Vision tower BF16 BF16
lm_head BF16 BF16

PLE

The 128 physical PLE embedding shards are quantized to FP8 E4M3FN using one shared FP32 scale across the complete logical embedding.

MTP

The 1,536 MTP routed-expert projections are stored using Quark-compatible 128×128 block FP8 with per-weight FP32 scale tensors.

Reference-guided layout

The additional FP8 targets were selected by comparing the corresponding tensor layouts of:

  • amd/Qwen3.8-Flash-Next-Quark-MXFP4
  • Qwen/Qwen3.8-Flash-Next-FP8
  • nvidia/Qwen3.8-Flash-Next-NVFP4

Weights are quantized from the AMD Quark checkpoint; weights are not copied from the FP8 or NVFP4 reference checkpoints.

Size

Approximate tensor payload:

Checkpoint Payload
AMD Quark MXFP4 source 169.72 GiB
This model 119.69 GiB
Reduction 50.03 GiB

The original MXFP4 payload is preserved. The reduction comes primarily from the PLE BF16 → FP8 conversion, with additional savings from the MTP FP8 conversion.

Validation

AMD source checkpoint

AMD reports the following GSM8K result for the source checkpoint:

Model GSM8K, 5-shot
Qwen/Qwen3.8-Flash-Next 96.8
amd/Qwen3.8-Flash-Next-Quark-MXFP4 96.5
Recovery 99.7%

The AMD checkpoint is a post-training Quark MXFP4 quantization of Qwen3.8-Flash-Next.

Full-vocabulary logit comparison

This model was compared directly against amd/Qwen3.8-Flash-Next-Quark-MXFP4 using teacher-forced, full-vocabulary logits.

KL direction:

KL(reference || candidate)

Metric Result
Scored tokens 28
Mean KL divergence 0.01542 nats/token
P95 KL 0.03851
P99 KL 0.04607
Maximum KL 0.04850
Top-1 agreement 85.71%
Reference NLL 5.44837
Candidate NLL 5.41924
NLL delta -0.02913
Perplexity ratio 0.97129

KLD was measured on the standard base-model forward; speculative MTP decoding was not exercised.

FP8 reconstruction

Converted tensors were also validated numerically after quantization. Sampled FP8 weight reconstruction produced approximately:

  • cosine similarity: ~0.99965
  • relative RMSE: ~0.026
  • observed clipping: 0

Model Architecture

  • Architecture: Qwen4ExpForConditionalGeneration
  • Input: Text, Image, Video
  • Output: Text
  • Base architecture: Qwen3.8-Flash-Next
  • Source quantization: AMD Quark OCP MXFP4
  • Additional quantization: FP8 E4M3FN / Quark block FP8
  • Format: Safetensors

Lineage

Qwen/Qwen3.8-Flash-Next

amd/Qwen3.8-Flash-Next-Quark-MXFP4

→ this mixed MXFP4 + FP8 checkpoint

See the upstream Qwen and AMD model cards for architecture details, original evaluation results, usage guidance, and licensing information.

License

This is a derivative checkpoint of amd/Qwen3.8-Flash-Next-Quark-MXFP4, itself derived from Qwen/Qwen3.8-Flash-Next.

Refer to the upstream AMD and Qwen repositories for the applicable licenses and terms.

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