{
  "hf_id": "Qwen/Qwen3.5-4B",
  "meta": {
    "title": "Qwen3.5-4B",
    "slug": "qwen3.5-4b",
    "provider": "Qwen",
    "description": "Qwen3.5 compact dense multimodal model (4B) — fits on 16 GB consumer GPUs with full 262K context or one Xeon 6 NUMA node or Intel Arc Pro B60/B70",
    "date_added": "2026-04-22",
    "date_updated": "2026-09-14",
    "tasks": [
      "multimodal",
      "text"
    ],
    "performance_headline": "Consumer-GPU-friendly Qwen3.5 dense with MTP support",
    "related_recipes": [
      "Qwen/Qwen3.5-9B",
      "Qwen/Qwen3.5-2B"
    ],
    "hardware": {
      "xeon6": "verified",
      "arc_pro_b60": "verified",
      "arc_pro_b70": "verified"
    }
  },
  "recommended_command": {
    "hardware": "arc_pro_b60",
    "strategy": "single_node_tp",
    "variant": "default",
    "node_count": 1,
    "deploy_type": "single_node",
    "env": {
      "VLLM_USE_RUST_FRONTEND": "1"
    },
    "docker_image": "vllm/vllm-openai-xpu:latest",
    "command": "vllm serve Qwen/Qwen3.5-4B \\\n  --trust-remote-code \\\n  --tensor-parallel-size 1 \\\n  --enforce-eager \\\n  --enable-auto-tool-choice \\\n  --tool-call-parser qwen3_coder \\\n  --reasoning-parser qwen3",
    "argv": [
      "vllm",
      "serve",
      "Qwen/Qwen3.5-4B",
      "--trust-remote-code",
      "--tensor-parallel-size",
      "1",
      "--enforce-eager",
      "--enable-auto-tool-choice",
      "--tool-call-parser",
      "qwen3_coder",
      "--reasoning-parser",
      "qwen3"
    ],
    "docker_command": "docker run --device /dev/dri \\\n  -v /dev/dri/by-path:/dev/dri/by-path --shm-size=16g \\\n  --privileged --ipc=host -p 8000:8000 \\\n  -v ~/.cache/huggingface:/root/.cache/huggingface \\\n  -e VLLM_USE_RUST_FRONTEND=1 \\\n  vllm/vllm-openai-xpu:latest Qwen/Qwen3.5-4B \\\n  --trust-remote-code \\\n  --tensor-parallel-size 1 \\\n  --enforce-eager \\\n  --enable-auto-tool-choice \\\n  --tool-call-parser qwen3_coder \\\n  --reasoning-parser qwen3",
    "docker_argv": [
      "docker",
      "run",
      "--device",
      "/dev/dri",
      "-v",
      "/dev/dri/by-path:/dev/dri/by-path",
      "--shm-size",
      "16g",
      "--privileged",
      "--ipc=host",
      "-p",
      "8000:8000",
      "-v",
      "~/.cache/huggingface:/root/.cache/huggingface",
      "-e",
      "VLLM_USE_RUST_FRONTEND=1",
      "vllm/vllm-openai-xpu:latest",
      "Qwen/Qwen3.5-4B",
      "--trust-remote-code",
      "--tensor-parallel-size",
      "1",
      "--enforce-eager",
      "--enable-auto-tool-choice",
      "--tool-call-parser",
      "qwen3_coder",
      "--reasoning-parser",
      "qwen3"
    ],
    "strategy_spec": {
      "name": "single_node_tp",
      "deploy_type": "single_node",
      "display_name": "Tensor Parallel",
      "short_label": "TP",
      "orientation": "latency",
      "description": "Single-node tensor parallel. Splits the model across all local GPUs. TP size is set to the GPU count at deploy time. The simplest multi-GPU strategy — works for all model architectures.\n",
      "hardware_match": {
        "min_gpus": 1,
        "max_gpus": 8,
        "multi_node": false
      },
      "vllm_args": [],
      "parallel_flag": "--tensor-parallel-size"
    },
    "hardware_profile": {
      "brand": "Intel",
      "generation": "xpu",
      "display_name": "Arc Pro B60",
      "description": "Intel Arc Pro B60 24 GB · 4-card node · vLLM XPU backend",
      "gpu_count": 4,
      "vram_gb": 96,
      "multi_node": false,
      "restricted": true
    },
    "by_hardware": {
      "arc_pro_b60": "/Qwen/Qwen3.5-4B/hw/arc_pro_b60.json",
      "xeon6": "/Qwen/Qwen3.5-4B/hw/xeon6.json",
      "arc_pro_b70": "/Qwen/Qwen3.5-4B/hw/arc_pro_b70.json"
    }
  },
  "model": {
    "model_id": "Qwen/Qwen3.5-4B",
    "min_vllm_version": "0.17.0",
    "default_frontend": "rust",
    "architecture": "dense",
    "parameter_count": "4B",
    "active_parameters": "4B",
    "context_length": 262144,
    "base_args": [
      "--trust-remote-code"
    ],
    "base_env": {},
    "install": {
      "pip": {
        "command": "uv venv\nsource .venv/bin/activate\nuv pip install -U vllm --torch-backend auto"
      },
      "docker": {
        "command": "docker pull vllm/vllm-openai:latest"
      }
    }
  },
  "features": {
    "tool_calling": {
      "description": "Enable automatic tool choice with Qwen3 Coder parser",
      "args": [
        "--enable-auto-tool-choice",
        "--tool-call-parser",
        "qwen3_coder"
      ]
    },
    "reasoning": {
      "description": "Enable chain-of-thought reasoning with Qwen3 parser",
      "args": [
        "--reasoning-parser",
        "qwen3"
      ]
    },
    "spec_decoding": {
      "description": "Multi-token prediction speculative decoding for lower latency",
      "args": [
        "--speculative-config",
        "{\"method\":\"mtp\",\"num_speculative_tokens\":1}"
      ]
    },
    "text_only": {
      "description": "Skip loading the vision encoder for text-only workloads.",
      "args": [
        "--language-model-only"
      ]
    },
    "long_context": {
      "description": "YaRN RoPE scaling past the native 262,144-token window to ~1,010,000 tokens. Static YaRN holds the scaling factor constant regardless of input length, so leave this off unless you actually serve long prompts; for ~524K, halve the factor to 2.0.",
      "args": [
        "--hf-overrides",
        "{\"text_config\": {\"rope_parameters\": {\"mrope_interleaved\": true, \"mrope_section\": [11, 11, 10], \"rope_type\": \"yarn\", \"rope_theta\": 10000000, \"partial_rotary_factor\": 0.25, \"factor\": 4.0, \"original_max_position_embeddings\": 262144}}}",
        "--max-model-len",
        "1010000"
      ],
      "env": {
        "VLLM_ALLOW_LONG_MAX_MODEL_LEN": "1"
      }
    }
  },
  "opt_in_features": [
    "spec_decoding",
    "text_only",
    "long_context"
  ],
  "variants": {
    "default": {
      "precision": "bf16",
      "vram_minimum_gb": 10,
      "description": "Full precision BF16 — fits on a single 16 GB GPU or one Xeon 6 NUMA node or one Intel Arc Pro B60/B70",
      "supported_hardware": [
        "xeon6",
        "arc_pro_b60",
        "arc_pro_b70"
      ]
    },
    "fp8": {
      "model_id": "RedHatAI/Qwen3.5-4B-FP8-dynamic",
      "precision": "fp8",
      "vram_minimum_gb": 5,
      "description": "RedHatAI FP8 (E4M3) with dynamic per-token activation quantization",
      "supported_hardware": [
        "arc_pro_b60",
        "arc_pro_b70"
      ],
      "extra_args": [
        "--kv-cache-dtype",
        "fp8"
      ],
      "json": "/RedHatAI/Qwen3.5-4B-FP8-dynamic.json"
    }
  },
  "hardware_overrides": {
    "xpu": {
      "extra_args": [
        "--enforce-eager"
      ]
    }
  },
  "guide": "## Overview\n\n[Qwen3.5-4B](https://huggingface.co/Qwen/Qwen3.5-4B) is the compact dense\nentry in the Qwen3.5 family — same gated delta networks architecture, vision\nencoder, 262K context, and MTP decoding as the larger siblings, sized for\n16 GB consumer GPUs.\n\n## Prerequisites\n\n- **vLLM version:** >= 0.17.0\n- **Hardware:** single 16 GB GPU (RTX 4080 / L4 / A10 / T4-24GB) or one Xeon 6 NUMA node or one Intel Arc Pro B60/B70\n\n### Install vLLM\n\n```bash\nuv venv\nsource .venv/bin/activate\nuv pip install -U vllm --torch-backend=auto\n```\n\n### pip (Intel Xeon 6 CPUs)\nFor Intel and AMD x86 CPUs, follow the [CPU pre-built wheels](https://docs.vllm.ai/en/latest/getting_started/installation/cpu/#pre-built-wheels) installation instructions.\n\n### Docker \n```bash\ndocker pull vllm/vllm-openai-xpu:latest  # Intel XPU (B60 / B70)\n```\n\n## Launching the Server\n\n```bash\nvllm serve Qwen/Qwen3.5-4B \\\n  --max-model-len 262144 \\\n  --reasoning-parser qwen3\n```\n\n### Intel Xeon 6 Deployment via Docker\n\nLaunch the x86 CPU vLLM Docker container for `Qwen/Qwen3.5-4B`:\n\n```bash\ndocker run \\\n  --privileged --ipc=host -p 8000:8000 \\\n  -v ~/.cache/huggingface:/root/.cache/huggingface \\\n  vllm/vllm-openai-cpu:latest-x86_64 Qwen/Qwen3.5-4B \\\n  --trust-remote-code \\\n  --tensor-parallel-size 1 \\\n  --enable-auto-tool-choice \\\n  --tool-call-parser qwen3_coder \\\n  --reasoning-parser qwen3\n```\n\n### Docker (Intel XPU B60 / B70)\n\nValidated on 1× Intel Arc Pro B60 / B70 (B60 24 GB, B70 32 GB per card) with the\nofficial vLLM XPU image `vllm/vllm-openai-xpu:latest`.\n\n```bash\ndocker run --device /dev/dri \\\n  -v /dev/dri/by-path:/dev/dri/by-path --shm-size=16g \\\n  --privileged --ipc=host -p 8000:8000 \\\n  -v ~/.cache/huggingface:/root/.cache/huggingface \\\n  vllm/vllm-openai-xpu:latest \\\n  Qwen/Qwen3.5-4B \\\n  --reasoning-parser qwen3 \\\n  --enforce-eager\n```\n\n\n### MTP speculative decoding\n\n```bash\nvllm serve Qwen/Qwen3.5-4B \\\n  --speculative-config '{\"method\": \"mtp\", \"num_speculative_tokens\": 1}' \\\n  --reasoning-parser qwen3\n```\n\n## Client Usage\n\n```python\nfrom openai import OpenAI\n\nclient = OpenAI(api_key=\"EMPTY\", base_url=\"http://localhost:8000/v1\")\nresp = client.chat.completions.create(\n    model=\"Qwen/Qwen3.5-4B\",\n    messages=[{\"role\": \"user\", \"content\": \"Hello!\"}],\n    max_tokens=128,\n)\nprint(resp.choices[0].message.content)\n```\n\n## Troubleshooting\n\n- **CUDA graph / Mamba cache size error:** reduce `--max-cudagraph-capture-size`.\n- **Disable reasoning:** add `--default-chat-template-kwargs '{\"enable_thinking\": false}'`.\n\n## References\n\n- [Model card](https://huggingface.co/Qwen/Qwen3.5-4B)\n- [Base checkpoint](https://huggingface.co/Qwen/Qwen3.5-4B-Base)\n",
  "source": {
    "source": "vllm",
    "repo": "vllm-project/vllm",
    "ref": "main",
    "sha": "564ac0de1b228568cafcbfbe8ccaccc82d6023eb",
    "path": "recipes/models/Qwen/Qwen3.5-4B.yaml",
    "edit_url": "https://github.com/vllm-project/vllm/edit/main/recipes/models/Qwen/Qwen3.5-4B.yaml",
    "overlays": []
  }
}