Olmo Hybrid and future LLM architectures

Olmo Hybrid and future LLM architectures

From Interconnects by Nathan Lambert

March 5, 2026 · 11 min

About this episode

The episode discusses the evolution and adoption of hybrid architectures in machine learning models, focusing on recent developments and historical context.

So-called hybrid architectures are far from new in open-weight models these days. We now have the recent Qwen 3.5 (previewed by Qwen3-Next ), Kimi Linear last fall (a smaller release than their flagship Kimi K2 models ), Nvidia’s Nemotron 3 Nano (with the bigger models expecting to drop soon), IBM Granite 4 , and other less notable models. This is one of those times when a research trend looks like it’s getting adopted everywhere at once (maybe the Muon optimizer too, soon?). To tell this story, we need to go back a few years to December 2023, when Mamba and Striped Hyena were taking the world by storm — asking the question: Do we need full attention in our models? These early models fizzled out, partially for the same reasons they’re hard today — tricky implementations, open-source tool problems, more headaches in training — but also because the models fell over a bit when scaled up. The hybrid models of the day weren’t quite good enough yet. These models are called hybrid because they mix these new recurrent neural network (RNN) modules with the traditional attention that made the transformer famous. They all work best with this mix of modules. The RNN layers keep part of the…

People in this episode

Host: Nathan Lambert

Topics covered

  • hybrid architectures
  • open-weight models
  • recurrent neural networks
  • transformer models
  • deep learning
  • machine learning trends

Keywords

  • hybrid models
  • RNN
  • attention mechanism
  • deep learning
  • machine learning
  • Qwen 3.5
  • Nvidia
  • IBM Granite 4

Mentioned in this episode

Organizations: Nvidia, IBM

Products: Qwen 3.5, Kimi Linear, Kimi K2, Nemotron 3 Nano, Granite 4, Muon optimizer, Mamba, Striped Hyena, LSTM

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