Measured on AMD RDNA4
2× Radeon AI PRO R9700 (gfx1201), tensor-parallel 2, vLLM 0.19.1 (image below).
- MTP draft acceptance (n=3): ≈66% average across a mixed code + 6k-context run — per-position
0.82 / 0.65 / 0.53, mean acceptance length ~3.0 (max 4) — rising to ~85% (length ~3.6) on
cache-warm short context. Lossless throughout.
- Tool-calling (
qwen3_xml) and vision confirmed working.
- Throughput (TP2, 256 output tokens, per-user / aggregate tok/s):
Table with columns: concurrent, short prompt, ~6k prompt| concurrent | short prompt | ~6k prompt |
|---|
| 1 | 84.6 / 85 | 103.8 / 104 |
| 16 | 51.8 / 803 | 50.1 / 767 |
| 32 | 40.8 / 1260 | 33.0 / 1010 |
| 64 | 30.7 / 1902 | 21.1 / 1268 |
| 96 | 22.5 / 2075 | 15.0 / 1293 |
| 128 | 20.2 / 1893 | 12.6 / 1284 |
Usable concurrency ceiling (per-user ≥ 20 tok/s): ~128 at short context, ~64 at 6k context.
Single-stream decode is bound by the dense 9B's active-parameter count; a single GPU (TP1) is also supported.
Run it on AMD RDNA4
Uses the prebuilt RDNA4 vLLM image
capicua25x/vllm-rocm-rdna4 (tag 0.19.1):
docker run --rm --network=host \ --device=/dev/kfd --device=/dev/dri \ --group-add=video --group-add=render --ipc=host --ulimit memlock=-1 \ capicua25x/vllm-rocm-rdna4:0.19.1 \ --model Capicua25x/Ornith-1.0-9B-MXFP4-Vision-MTP \ --served-model-name ornith --trust-remote-code \ --tensor-parallel-size 2 \ --gpu-memory-utilization 0.90 \ --max-model-len 16384 \ --attention-backend TRITON_ATTN \ --enable-prefix-caching \ --enable-auto-tool-choice --tool-call-parser qwen3_xml --reasoning-parser qwen3 \ --speculative-config '{"method":"mtp","num_speculative_tokens":3}'
The settings that actually matter on RDNA4
--attention-backend TRITON_ATTN — required on gfx1201.
--speculative-config '{"method":"mtp","num_speculative_tokens":3}' — enables the grafted MTP head.
n=3 maximizes throughput; n=1–2 maximize per-token acceptance. Tune per workload.
--tool-call-parser qwen3_xml --reasoning-parser qwen3 — Qwen3.5-family tool-calling + reasoning split.
--trust-remote-code — the qwen3_5 vision architecture.
- Single GPU works too:
--tensor-parallel-size 1 and pass one render node
(e.g. --device=/dev/dri/renderD128).
How it was built (reproducible)
- MXFP4 quantize Ornith-1.0-9B with
compressed-tensors (4-bit float, group 32, symmetric;
lm_head / embed_tokens / norms / vision tower left BF16).
- Graft the 15
mtp.* head tensors from protoLabsAI/Ornith-1.0-9B-MTP into a new
model-mtp.safetensors shard and patch model.safetensors.index.json.
- Mark the head unquantized — add its Linear modules (
mtp.fc, mtp.layers.0.self_attn.*,
mtp.layers.0.mlp.*) to quantization_config.ignore, so vLLM's compressed-tensors loader keeps the
BF16 head as-is instead of expecting MXFP4 weight-scales. This is the one mixed-precision gotcha.
Step 1 (the MXFP4 quantize) is scripted in quantize_mxfp4.py (weight-only MXFP4A16, group 32, data-free — deterministic/byte-reproducible). Steps 2–3 are scripted in recipe_graft_mxfp4.py (run against an MXFP4
compressed-tensors trunk + the protoLabs head). The head's distillation recipe lives upstream at
protoLabsAI/Ornith-1.0-9B-MTP.
Credits
- DeepReinforce —
Ornith-1.0-9B, the base model (MIT).
- protoLabs —
Ornith-1.0-9B-MTP, the KL-distilled MTP draft head and its recipe (MIT).
- Qwen / Alibaba — the Qwen3.5 architecture the MTP head derives from (the head was initialized from
Qwen/Qwen3.5-9B's mtp.* tensors).
- vLLM and compressed-tensors — serving stack and quantization format.
- Rob Smith (
tcclaviger) — the RDNA4 vLLM base image that made gfx1201 serving possible. The image this model runs on is a forward-port of his work — without it, none of this runs.
License
MIT. This is a derivative of Ornith-1.0-9B (MIT); merging the MTP head (MIT) produces a derivative whose MIT terms carry.