int8 search + fp32 rescoring lifts recall@100 from 97.24% to 99.94%

tomaarsen · x · 2026-11-10

tomaarsen shares a cheap trick to negate int8 quantization loss in vector image search: use the int8 index to fetch candidates, load their fp16 embeddings from disk, and rescore against the fp32 query to get a new top 30. Versus exact fp32 search, plain int8 gets 97.24% recall@100, while int8 + fp16/fp32 rescoring reaches 99.94% — with minimal added cost before loading the actual images for the user.

Related event: Sentence Transformers maintainer demos int8-quantized retrieval in milliseconds(4 posts)→

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