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Open weightsZyphra/10 trustVerified

Zamba2 2.7B

A 2.7B hybrid Mamba2-attention model built for on-device inference: no full KV cache, tiny memory footprint, outsized instruction scores.

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About

Zamba2-2.7B is Zyphra's small hybrid model that replaces most of the transformer stack with Mamba2 state-space blocks, keeping just two shared attention layers threaded through the network in an ABAB pattern. LoRA-style projectors on the shared MLPs let each invocation specialize slightly without paying for full separate layers. The result is a 2.7B model trained on 2 trillion tokens that Zyphra positions squarely at on-device and edge deployment, where the missing full KV cache keeps memory use far below a comparable transformer.

On the provider's own numbers, the instruct variant scores 72.4 aggregate MT-Bench and 48.0 on IFEval, ahead of Gemma2-2B-Instruct and even Mistral-7B-Instruct on those two suites. Inference is the real pitch: lower time to first token and faster generation with a smaller memory footprint than transformer baselines. The tradeoff is ecosystem friction. Mamba kernels want specific builds, community fine-tunes are thin next to Llama-family models, and every headline number comes from Zyphra itself.

Specs

Context window

4K tokens base; optional long-context variant via use_long_context flag

Pricing

Free, self-hosted

Free quota

No quota; weights freely downloadable from Hugging Face

API access

No hosted API; Hugging Face weights with Transformers and Unsloth support

Weights

Open weights

Released

Not disclosed

Benchmarks

  • Aggregate MT-Bench: 72.40; IFEval: 48.02 (Zamba2-2.7B-Instruct, provider-reported)
  • Mistral-7B-Instruct: 66.4 / 45.3; Gemma2-2B-Instruct: 51.69 / 42.20 on the same two suites (provider-reported)
  • Latency/memory advantage over transformer baselines claimed, no absolute figures published

Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.

Use cases

on-device-aiedge-inferenceinstruction-followinglow-latency-chat

Trust score — 7/10

/10 trustVerified

Scored 7/10 (verified tier, metrics-v1). Evidence: Apache 2.0 license and hybrid Mamba2 architecture confirmed on the official Hugging Face model cards (Zyphra/Zamba2-2.7B); MT-Bench 72.40 and IFEval 48.02 figures from Zyphra's own model card; 2024-11-22 release date from the Transformers model docs. Strengths: genuinely novel efficient architecture, permissive license, strong provider-reported instruction scores for the size. Docked for: (1) all headline benchmarks are provider-reported with no independent replication found; (2) small vendor and thin community ecosystem mean fewer fine-tunes and tooling than transformer peers. License: Apache-2.0.

How the trust score is built

Full methodology →
Adoption · stars/downloads, log-scaled vs peers
5.0/10
Maintenance · recency, releases, issue load
5.0/10
Openness · license + docs
9.0/10
Manual review · sanity read + red-flag check
7.0/10
  • · Zyphra; released 2024-11-22
  • · Hybrid Mamba2 + shared attention
  • · All benchmarks provider-reported; thin ecosystem

Sources