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Gemma / Dense

gemma-4-31B-it

The dense control for Gemma’s MoE experiment

Open-weight releaseSources checked 2026-09-13

Use 31B as a dense quality baseline alongside 26B-A4B. A dense model can be the simpler operational choice when its extra active compute is acceptable and it behaves better on your tasks.

30.7Breported total parameters
Denseactive parameters per token
262,144configured token positions

Publisher-reported, rounded model count; not an exact tensor census. Multimodal components and packaging can change the artifact size.

Evaluate it for

Dense multimodal serving and comparisons that keep the model family fixed.

Choose another path when

An audio-first application or a memory allocation with no room beyond roughly 61.4 GB of BF16 language-weight arithmetic.

Release context

Why this release matters

Its role in the April release is complementary to the MoE. The model accepts text, images and video; audio support belongs to other variants and must not be inferred from the Gemma brand.

Release evidence · Follow the Gemma timeline →

Deployment starting points

Which hardware, how many, at what precision?

Start with an exact artifact and an engine that supports it. A configuration below is evidence of a documented path; its device count does not promise a particular throughput or concurrency.

No certified hardware configuration in this edition

An audio-first application or a memory allocation with no room beyond roughly 61.4 GB of BF16 language-weight arithmetic.

The pinned model card establishes the architecture. It does not, by itself, prove that a particular GPU count runs this checkpoint at your target context. The capacity screen below helps rule out undersized allocations; a successful load and workload test are still required.

62.55 GB of tensor data in the pinned index

This is the index’s reported tensor payload, in decimal GB. It excludes file headers and runtime memory. Mixed precision, conversion and host/device placement determine how much GPU memory the loaded model needs.

Inspect the exact index metadata →
Capacity screen: would the weights fit?

This estimates inference memory for a hypothetical uniform precision. It is useful for rejecting an allocation that is too small. It does not establish a working deployment or estimate training memory.

Weights only, before requests or runtime buffers. These formats are mathematical scenarios, not claims that each artifact exists.
RepresentationApproximate weight floorWhat remains to budget
16-bit uniform61.4 GBCache, modality state, workspace, quantization metadata and uneven sharding
8-bit uniform30.7 GBCache, modality state, workspace, quantization metadata and uneven sharding
4-bit uniform15.35 GBCache, modality state, workspace, quantization metadata and uneven sharding

Enter the total across the whole model replica, not per GPU: KV or recurrent cache for all concurrent requests, image/audio state and execution workspace. There is no universal default. We additionally leave 15% of each GPU unused.

61.4 GB for hypothetical weights

Enter a request-and-buffer budget to calculate the aggregate capacity requirement.

A count of one does not prove the engine supports this GPU. A count above one does not prove the model shards evenly or communicates efficiently. Publisher-reported, rounded model count; not an exact tensor census. Multimodal components and packaging can change the artifact size.

Inspect the GPU and its interconnect →

Architecture in practice

What the serving engine has to do

Local and global layers read different spans.

A token enters a layerthe layer type selects its spanLocal attention layerread a bounded token windowGlobal attention layerread across available contextWindowed KV statebudget follows the local windowGlobal KV statebudget grows with context

Window length and layer ratio are checkpoint-specific.

Full-context state remains for global layers.

Schematic of a sliding-window and full-attention stack, not a literal layer ordering. Local layers attend within a bounded token window; global layers attend across the available context. These are both attention layers, not a recurrent-state architecture.

Mechanism schematic based on the pinned model card and configuration. It explains a design principle; it is not a full implementation graph.

Inspect the full checkpoint specifications
Inspected fields for this exact revision. KV heads alone do not describe latent, hybrid or shared-cache layouts.
Exact checkpointgoogle/gemma-4-31B-it
Text model typegemma4_text
Layers60
Hidden width5,376
Attention / KV heads32 / 16
Head dimension256
Routed / selected expertsNot verified / Not verified
Configured positions262,144
Documented extensionNot recorded for this checkpoint
Inputs → outputtext, image, video → text
License metadataapache-2.0

50 sliding attention layers; 10 full attention layers. These counts describe the configured pattern.

Open weights do not imply unrestricted use. Read the applicable license terms linked from the pinned card.

A useful comparison

What else belongs on the shortlist?

The MoE is the closest architecture comparison; Qwen3.8-27B is a newer dense multimodal alternative.

2 Apr 2026

gemma-4-26B-A4B-it

Sparse compute in a workstation-sized family

25.2B reported total · text + image + video

14 Aug 2026

Qwen3.8-27B

A current dense baseline before you scale out

27B reported total · text + image + video

These are editorial comparison candidates. We have not run a matched quality or serving benchmark, so this is not a ranking.

Prepare to explain it

The interview lesson

Explain why fewer stored weights and less active compute are different optimization targets.

Attention layouts · Quantization · Courses and worked examples

For a deployment evaluation, record exact weights, precision, engine, device count, interconnect, prompt/output lengths and concurrency. Report task success, errors, TTFT, TPOT and useful throughput together.

Sources and citation

Our assessment is editorial judgment based on the linked architecture and deployment evidence. Model facts are publisher-reported or attributed to runtime maintainers; no independent GPU benchmark was run.

AI Infra Interviews, “gemma-4-31B-it: release, architecture and deployment”, checked 2026-09-13. Preserve this date and the exact checkpoint when citing.

Model and research notes as JSON · Google DeepMind profile