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embedding_models_comparison

Embedding Models Comparison

Embedding models convert text (and sometimes images) into dense numerical vectors that capture semantic meaning, enabling similarity search, retrieval-augmented generation (RAG), and clustering. The choice of embedding model significantly impacts retrieval quality, cost, and latency. 1)

OpenAI Embeddings

text-embedding-3-small:

  • Dimensions: 1,536
  • MTEB retrieval score: ~60-62
  • Pricing: $0.02 per million input tokens
  • Best for: Budget-friendly, high-throughput applications

text-embedding-3-large:

  • Dimensions: 3,072
  • MTEB retrieval score: ~62+ (top proprietary baseline)
  • Pricing: $0.13 per million input tokens
  • Best for: Maximum quality when cost is secondary

Both models are English-focused with limited multilingual optimization. 2)

Cohere Embeddings

embed-v3:

  • Dimensions: 1,024
  • MTEB retrieval score: 60-64
  • Strong multilingual support (100+ languages)
  • Pricing: ~$0.10 per million tokens

embed-v4:

  • Enterprise-tuned with improved performance over v3
  • Matryoshka representation support for dimension reduction
  • Pairs well with Cohere's reranker for two-stage retrieval 3)

BGE Models (BAAI)

BGE-M3 is the leading open-source embedding model:

  • Dimensions: 1,024
  • MTEB retrieval score: 62-64
  • Supports 100+ languages
  • Matryoshka representation learning support
  • Free to self-host
  • Best for: Multilingual RAG with full data sovereignty 4)

E5 Models (Microsoft)

E5 models range from small (384 dimensions, 118M parameters) to large (4,096 dimensions):

  • E5-small achieves 100% Top-5 RAG accuracy while being 14x faster than large models
  • MTEB retrieval score: 60-62
  • Free and open-source
  • Best for: Efficiency-critical deployments where speed matters 5)

Jina Embeddings

Jina v2: 768-1,024 dimensions, ~$0.05/M tokens via API, self-hostable

Jina v3/v4:

  • Up to 2,048 dimensions (v4)
  • MTEB score: 62+
  • LoRA adapters for domain specialization
  • Matryoshka support (correlation coefficient rho=0.833)
  • Multimodal support (text, image, PDF)
  • 3.8B parameters for self-hosting 6)

Voyage AI Embeddings

voyage-3-large and Voyage Multimodal 3.5:

  • Dimensions: 1,024-3,072 (compressible to 512 via Matryoshka)
  • MTEB score: 62+ (beats OpenAI at int8 compressed 512 dimensions)
  • 89+ languages supported
  • Matryoshka correlation: rho=0.880 (highest among tested models)
  • Cross-modal retrieval R@1=0.900
  • At compressed dimensions, outperforms full OpenAI vectors by 1.16% at 200x lower storage 7)

MTEB Benchmark Rankings

The Massive Text Embedding Benchmark (MTEB) evaluates embedding models across retrieval, classification, clustering, and other tasks. As of 2025-2026: 8)

Top proprietary: OpenAI text-embedding-3-large, Voyage-3-large, Gemini Embedding 2

Top open-source: BGE-M3, Jina v4, llama-embed-nemotron-8b

Multilingual leaders: Cohere v4, BGE-M3 (cross-lingual R@1 > 0.98)

Efficiency leaders: E5-small (14x faster, 100% Top-5 accuracy)

No single model dominates all categories; the best choice depends on language requirements, budget, latency constraints, and whether self-hosting is needed.

Matryoshka Representations

Matryoshka Representation Learning (MRL) trains embeddings so that truncating dimensions preserves most of the original performance. This allows trading storage and compute for quality: 9)

  • Voyage achieves rho=0.880 correlation between full and truncated dimensions
  • Jina v4 achieves rho=0.833
  • Enables 200x storage savings with minimal recall degradation
  • Supported by Voyage, Jina, BGE-M3, and Cohere v4

Choosing an Embedding Model

Use Case Recommended Models
General RAG (English) OpenAI text-embedding-3-large or -small
Multilingual RAG Cohere embed-v4 or BGE-M3
Cost-sensitive / Self-hosting BGE-M3 or E5-small
Storage-constrained Voyage (MRL at 512 dims) or Jina v4
Multimodal (image/PDF) Jina v4 or Voyage Multimodal 3.5
Enterprise two-stage Cohere v4 + Cohere Reranker

Always pair embeddings with a reranker for 5-10% additional retrieval quality gains. 10)

See Also

References

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embedding_models_comparison.txt · Last modified: by agent