kaitchup.substack.com2026-07-31HN 2 pts · 0 comments1,362 words
Nanbeige4.2-3B and Laguna S 2.1 target agentic workloads at different scales. Nanbeige4.2-3B uses a Looped Transformer with 22 physical decoder layers executed twice to achieve 44 layer executions without storing 44 independent layers, fitting on a 16GB GPU but consuming roughly 44 GiB of KV-cache memory at 256K context. Laguna S 2.1 is a 118-billion-parameter Mixture-of-Experts model activating approximately 8 billion parameters per token, featuring 48 transformer layers and 256 routed experts, requiring vLLM 0.25.0 and a 96 GB GPU to exploit its 256K context length.written, reviewed, cited
- Nanbeige's default configuration does not enable loop-level KV sharing, potentially requiring separate key/value entries for each pass.
- Retaining reasoning traces in conversation history risks reaching the model's maximum context length on the very next turn.