Quality
Table with columns: this model, bf16 | this model | bf16 |
|---|
| WikiText-2 perplexity | 7.034 | 7.081 |
| KL divergence vs bf16 (top-256, nats) | 0.0091 | 0 |
| Top-1 token match with bf16 | 95.28% | 100% |
| MMLU 5-shot | 82.4% | — |
| GSM8K flexible / strict | 97.5% / 96.6% | — / — |
| HumanEval / HumanEval+ | 96.3% / 92.1% | — / — |
bf16 = the unquantized source model served on the same image; — = not measured.
Perplexity is cross-stack — this model at tensor parallel 1, bf16 at 2 — and wikitext-2's train split is in the stage-2 calibration mix, so a reading at or below bf16 is not evidence of a general gain.
GSM8K and HumanEval are chat-templated with reasoning on, greedy, on a Qwen chat template at reasoning_effort=xhigh rather than the default template the command below uses; both scores move with that choice.
2× Radeon AI PRO R9700, TP=2, DFlash2-FP8 drafter (7 tokens), KV pinned with KV_MEM=13500000000, tokens/s.
Table | |
|---|
| Single-stream decode | 135.7 |
| Concurrent decode c1 / c2 / c4 / c8 | 122.2 / 213.9 / 328.4 / 401.6 |
| Prefill 2k / 8k / 16k / 32k / 60k | 3312 / 3599 / 3555 / 3453 / 3333 |
| KV cache tokens | 685,554 |
| Weights per GPU | 12.85 GiB |
Each row is a single measured run, on a newer radiance build than the 0.9.3 image the setup below installs, so expect these figures to move. KV capacity follows the pin, not the weight format.
How to run
Requirements
- Two AMD RDNA4 (gfx1201) GPUs. The kernels are built for that architecture only; measured on 2 x Radeon AI PRO R9700 at tensor parallel 2.
- Linux with the
amdgpu kernel driver loaded, so /dev/kfd and /dev/dri exist. ROCm userspace ships inside the image, so there is no host ROCm install.
docker or podman (auto-detected), and a host git and python3 (standard library only).
- Disk for the checkpoint, plus about 12 GiB for the DFlash2-FP8 drafter and the
stilldeadcode/vllm-radiance:0.9.3 image, both of which setup fetches.
Two ways to get the code. MXFP6 support is open as a pull request to ggz14/radiance-vllm-mxfp4 (#46). Clone the fork below to run it today, or wait for the pull request to merge and clone ggz14's repository instead — the commands are the same either way.
Install and serve
git clone https://codeberg.org/hugypufy/radiance-vllm-mxfp4 && cd radiance-vllm-mxfp4
SRC_REPO=hugypufy/Qwen3.8-27B-PARO-MXFP6 SNAP=~/models/Qwen3.8-27B-PARO-MXFP6 \
./setup-paroquant.sh --mxfp6 --yes
MODEL_DIR=Qwen3.8-27B-PARO-MXFP6 MODE=prod SPEC=7 ./paroquant/run_paroquant.sh
Setup is one-time and safe to re-run. The launcher reads the quantization format from config.json and sets the kernel knobs it needs, so that is the whole serve command; the server answers as Qwen3.8-PARO on http://localhost:8080/v1. Every start patches vLLM inside the container and compiles the ParoQuant kernels for gfx1201, about two minutes, before the model loads; the first start also compiles Triton and inductor graphs, which adds several minutes and is cached for later starts.
Test
curl -s http://localhost:8080/v1/chat/completions -H 'Content-Type: application/json' \
-d '{"model":"Qwen3.8-PARO","messages":[{"role":"user","content":"Hello!"}]}'
Options — set as environment variables on the serve command.
Table with columns: Variable, Default, Notes| Variable | Default | Notes |
|---|
KV_MEM | unset; the pool is sized from GPU_UTIL (0.92) | Pin the KV cache in bytes per GPU; the figures above used KV_MEM=13500000000 |
SPEC | 5 | DFlash2 draft tokens per step. The numbers above used 7 |
CHAT_TEMPLATE | the repository's qwen-fixed-v22.3.jinja |
- Weights: OCP MXFP6 E2M3, one e8m0 scale per 32 weights — 6.25 bits/weight.
- Rotations: from z-lab/Qwen3.8-27B-PARO, frozen.
- Recipe: round-to-nearest, then a stage-2 fine-tune (FT) of weights and block scales, rotations frozen.
- fp16: visual tower,
linear_attn.in_proj_a/b, linear_attn.conv1d / A_log / dt_bias, lm_head, embeddings, norms, and the rotation theta / channel_scales (pairs are int16). MTP head not included.
Licence
Base weights Qwen/Qwen3.8-27B are Apache-2.0; this derivative is distributed under the same licence (LICENSE).
Modified derivative, not made or endorsed by the Qwen team / Alibaba Cloud or by z-lab; NOTICE lists the changes.
Rotations from z-lab/Qwen3.8-27B-PARO (Apache-2.0).