The Big LLM Architecture Comparison

Last updated: Apr 2, 2026 (added Gemma 4 in section 23) It has been seven years since the original GPT architecture was developed. At first glance, looking back at GPT-2 (2019) and forward to DeepSeek V3 and Llama 4 (2024-2025), one might be surprised at how structurally similar these models still are. Sure, positional embeddings have evolved from absolute to rotational (RoPE), Multi-Head…