This episode examines the architecture and efficiency of Large Language Models (LLMs), focusing heavily on optimizing the attention mechanism and exploring alternatives like State Space Models (SSMs). Several papers introduce and analyze methods to overcome the quadratic complexity of standard self-attention, including Grouped-Query Attention (GQA), Sliding Window Attention (SWA), and the hardware-aware optimizations of FlashAttention. A significant portion of the research centers on Mamba-based models and hybrid architectures that combine SSMs with attention layers, demonstrating that these hybrids, such as the Mamba-2-Hybrid, can achieve better performance on memory recall and long-context tasks than pure Transformers while maintaining efficiency. Finally, one source investigates the internal reasoning of attention mechanisms, proposing that a "preplan-and-anchor" rhythm can be identified and leveraged to create more effective reinforcement learning strategies for fine-grained policy optimization