NVIDIA's new Jet-Nemotron model family, which introduces a hybrid-architecture approach to Large Language Models (LLMs) to significantly improve efficiency without sacrificing accuracy. This innovation is primarily driven by two key technologies: Post Neural Architecture Search (PostNAS), a method for "retrofitting" existing models to identify and replace less critical full-attention layers with more efficient ones, and JetBlock, a novel linear attention module. The core idea is that not all attention layers are equally important, allowing for a drastic reduction in the Key-Value (KV) Cache size, leading to up to a 53.6x increase in decoding throughput and a 98% potential cost reduction for inference. Jet-Nemotron aims to set a new standard for LLM evaluation, emphasizing real-world performance and hardware efficiency across a range of devices, from data centers to edge devices, making high-performance AI more economically viable and accessible.