Mixture of Experts Explained: How the Smartest AI Models Use Less Than 5% of Their “Brain”

"The world’s most advanced open-source AI models don’t fire all their parameters at once. Instead, they use a technique called Mixture of Experts (MoE)—activating only the specific “experts” needed for each task.

A tiny router decides which expert regions to use, meaning less than 5% of the model activates per token. These experts run in parallel across many GPUs and share their results to generate a final answer.

But MoEs only scale efficiently if all those experts can communicate instantly."