Granite 4.1 Guardian 8B

Overview

IBM's Granite 4.1 Guardian is a dense 8B safety model for moderating and judging LLM outputs — prompt/response filtering and LLM-as-judge — with a 128k context and Apache 2.0 license. Released June 2026.

When to pick this model

• Content moderation pipelines that need to flag unsafe LLM outputs
• LLM-as-judge setups scoring or evaluating other models' responses
• Prompt and response filtering in production LLM applications
• Guardrail layers requiring an Apache 2.0-licensed, commercially deployable model

VRAM requirements by quantization

Quantization	VRAM required
Q4_K_M (recommended)	4.6 GB
Q5_K_M	6 GB
Q8_0	9 GB
FP16 (no quantization)	16 GB

VRAM figures include model weights plus a typical 8k KV cache and ~600 MB runtime overhead (Ollama / llama.cpp baseline). Add headroom for higher context lengths.

In practice, Granite 4.1 Guardian 8B fits an 8 GB consumer card at Q4_K_M (4.6 GB). Stepping up to Q8_0 nearly doubles the footprint to 9 GB, and unquantized FP16 weights take 16 GB — plan your GPU around the Q4 or Q5 figure unless you specifically need the higher fidelity.

Without a GPU, Granite 4.1 Guardian 8B needs roughly 10 GB of system RAM to run on CPU via llama.cpp or Ollama — workable for background jobs, but far slower than GPU inference. Throughput estimates from our compatibility engine: around 12 tokens/sec on entry-level GPUs, on the order of 35 tokens/sec on a mid-range card, and up to 90 tokens/sec on high-end hardware — assuming the chosen quantization fully fits in VRAM.

What hardware do you need

The table below matches Granite 4.1 Guardian 8B to common GPU memory tiers, using the highest-fidelity quantization that fully fits each card class. Spilling layers to system RAM works but costs most of the speed, so size your card to the quantization you actually want to run.

GPU memory	Example cards	Best fit for Granite 4.1 Guardian 8B
8 GB	RTX 5070 Laptop, RTX 5060, RTX 5060 Ti 8GB	Q5_K_M (6 GB used)
12 GB	RTX 5070, RTX 5070 Ti Laptop, RTX 4080 Laptop	Q8_0 (9 GB used)
16 GB	RTX 5080, RTX 4080 Super, Radeon RX 9070 XT	FP16 (16 GB used)
24 GB	RTX 4090, Radeon RX 7900 XTX, RTX 5090 Laptop	FP16 (16 GB used)
32 GB	RTX 5090	FP16 (16 GB used)

Which GPU should you buy to run Granite 4.1 Guardian 8B?

To run Granite 4.1 Guardian 8B locally at Q4, you need ~4.6 GB of VRAM. The best value for this is a RTX 5060 (8 GB VRAM).

Strengths

• Apache 2.0, cleared for commercial use
• Purpose-built for safety and moderation tasks
• Native 128k context
• Official Ollama tag available

Limitations

• Not a general-purpose chat model — built for judging/moderation
• Gated weights on Hugging Face (click-through required)
• Public benchmarks are still limited

Typical workloads

In our catalog grid, Granite 4.1 Guardian 8B is filed under Content Moderation, LLM-as-Judge, Prompt/Response Filtering — the use cases where its size/quality trade-off makes the most sense. Its tags translate to concrete workloads: multi-step reasoning and math-flavoured tasks.

The 125k-token context window covers long chats and mid-sized documents, though very large retrieval workloads will need chunking. The Apache 2.0 license is permissive, so shipping it inside a commercial product raises no special legal questions.

Architecture & training

Architecture: Dense transformer · 8B parameters · IBM Granite 4.1 family specialized for safety/judging

Training: Guardian variant of Granite 4.1 (IBM): tuned for moderation, LLM-as-judge, and prompt/response filtering. Apache 2.0, 128k context.

Quick start

ollama pull granite4.1-guardian

Or use the open-source MCP server to query this model from Claude Desktop, Cursor, or any MCP-compatible client.

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Frequently asked questions

How much VRAM does Granite 4.1 Guardian 8B need?

At the recommended Q4_K_M quantization, Granite 4.1 Guardian 8B needs about 4.6 GB of VRAM. Q8_0 takes 9 GB, and unquantized FP16 weights take 16 GB.

Can Granite 4.1 Guardian 8B run without a GPU?

Yes — with roughly 10 GB of system RAM it runs CPU-only through llama.cpp or Ollama. Expect a fraction of GPU speed, which is fine for background or batch jobs but slow for interactive chat.

What context window does Granite 4.1 Guardian 8B support?

Granite 4.1 Guardian 8B supports a 125k-token context window (128,000 tokens).

Can I use Granite 4.1 Guardian 8B commercially?

Yes. Granite 4.1 Guardian 8B is released under Apache 2.0, a permissive open-source license that allows commercial use, modification and redistribution.

How fast is Granite 4.1 Guardian 8B on consumer hardware?

Our compatibility engine estimates on the order of 35 tokens/sec on a mid-range GPU and up to 90 tokens/sec on high-end cards, assuming the quantization fully fits in VRAM.

Which quantization of Granite 4.1 Guardian 8B should I download first?

Start with Q4_K_M (4.6 GB) — the standard size/quality sweet spot. Step up to Q5_K_M or Q8_0 only if you have VRAM headroom. It already fits an 8 GB card at Q5_K_M.