Decoder. plain-English AI glossary

Sparse Mixture

▲ Rising

Also called Sparse Mixture of Experts

A mixture-of-experts model where only a few experts fire per token, keeping a giant model cheap to run.

Think of it like

Like a huge consulting firm where any one question only pulls in two specialists, not the entire staff.

Example

A model with 100 billion total parameters but only 12 billion active per token is a sparse mixture.

How it actually works

“Sparse” means each token activates just a small subset of the experts, so total capacity can be enormous while per-token compute stays modest. This decouples a model’s knowledge (total params) from its running cost (active params). The trade-offs are memory to hold all the experts and the routing quality that decides which few actually run.

For product teams

How a model can be “huge” in capability yet still affordable per token.

For engineers

An MoE with top-k expert activation, decoupling total from active parameters.

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