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Gemma / Lab profile

Google DeepMind

Gemma is a family of different design choices, not just different sizes.

Gemma 4 is a particularly useful learning family because its branches solve different problems. The April release includes effective-parameter E models, a conventional dense model and an MoE. June adds a unified encoder-free multimodal model and an experimental diffusion generator.

Architecture trajectory

What connects these models?

E2B and E4B use per-layer embedding tables, so effective parameters differ from total stored parameters. The 26B-A4B and 31B pair exposes the MoE-versus-dense tradeoff. The 12B model changes the multimodal input path; DiffusionGemma changes the generation loop itself.

Output emerges through repeated refinement.

Initial token blockcandidate outputRefinement passupdate token predictionsFinal textafter the stopping rule

Measure final-answer quality and completion time.

Autoregressive TPOT is not a universal comparison.

Conceptual diffusion-generation loop. A candidate token block is refined repeatedly before the final text is returned. The exact schedule belongs to the model and runtime; this drawing does not specify a fixed number of steps.

Newest first / grouped sequence, not a time scale

The Gemma timeline

  1. diffusiongemma-26B-A4B-it

    A different generation loop, not a drop-in speed setting

    The June research release generates through iterative refinement rather than the standard one-token-at-a-time loop. That makes it historically useful even if your current service remains autoregressive.

    Release evidence ↗

  2. gemma-4-12B-it

    One model path for text, vision and audio

    The June addition introduced a unified input path within the Gemma 4 family. It is an architectural branch, not simply a halfway size between E4B and 26B-A4B.

    Release evidence ↗

  3. gemma-4-26B-A4B-it

    Sparse compute in a workstation-sized family

    The April family offered both dense and MoE choices. The reported 25.2B total and 3.8B active values make the rounded 26B-A4B name precise enough to reason about.

    Release evidence ↗

  4. gemma-4-31B-it

    The dense control for Gemma’s MoE experiment

    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 ↗

  5. gemma-4-E2B-it

    “Effective” is a compute label, not the download size

    Per-layer embedding tables are the reason the E label differs from a conventional dense parameter label. Placement and quantization of those tables can change the practical footprint substantially.

    Release evidence ↗

  6. gemma-4-E4B-it

    More effective capacity, with tables still to place

    Like E2B, it makes conditional embedding storage visible in a small-model setting. This is a useful bridge to the much larger conditional-memory systems introduced later in 2026.

    Release evidence ↗

Which other labs should you compare?

Use Qwen’s small dense models as alternatives to the E variants, while explicitly accounting for embedding storage. Compare Gemma 31B with Qwen3.8-27B or Muse Glimmer for mid-sized multimodal applications. DiffusionGemma needs its own quality-versus-completion-time experiment against autoregressive Gemma.

Qwen

Alibaba Qwen

One family spans tiny dense models, coding MoEs and conditional memory.

Muse Glimmer

Meta

A local-agent release includes the runtime around the model.

Interview preparation

What you should be able to explain

Explain three independent choices: where inputs become model tokens, which parameters execute per token, and how output tokens are generated. Gemma offers a concrete example for each.

Study the underlying systems → · Get the illustrated report →

Sources and scope

Checked 13 September 2026. Assessments and comparison candidates are our interpretation of the cited designs, not measured cross-lab rankings. Each timeline entry links to its release evidence; model pages preserve pinned card and configuration sources.