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Raschka & Lambert on Lex Fridman: Why Post-Training Won 2025

Rlvr and inference time scaling, not architecture, drove 2025 AI gains. Deepseek open-weight releases showed frontier performance need not be closed-source.

Lex FridmanhostSebastian RaschkaguestNathan Lambertguest
Jan 31, 20264h 25mWatch on YouTube ↗

CHAPTERS

  1. 0:00 – 1:57

    Introduction

  2. 1:57 – 10:38

    China vs US: Who wins the AI race?

  3. 10:38 – 21:38

    ChatGPT vs Claude vs Gemini vs Grok: Who is winning?

  4. 21:38 – 28:29

    Best AI for coding

  5. 28:29 – 40:08

    Open Source vs Closed Source LLMs

  6. 40:08 – 48:05

    Transformers: Evolution of LLMs since 2019

  7. 48:05 – 1:04:12

    AI Scaling Laws: Are they dead or still holding?

  8. 1:04:12 – 1:37:18

    How AI is trained: Pre-training, Mid-training, and Post-training

  9. 1:37:18 – 1:58:11

    Post-training explained: Exciting new research directions in LLMs

  10. 1:58:11 – 2:21:03

    Advice for beginners on how to get into AI development & research

  11. 2:21:03 – 2:24:49

    Work culture in AI (72+ hour weeks)

  12. 2:24:49 – 2:28:46

    Silicon Valley bubble

  13. 2:28:46 – 2:34:28

    Text diffusion models and other new research directions

  14. 2:38:44 – 2:44:06

    Continual learning

  15. 2:59:31 – 3:06:47

    Timeline to AGI

  16. 3:06:47 – 3:25:18

    Will AI replace programmers?

  17. 3:25:18 – 3:32:07

    Is the dream of AGI dying?

  18. 3:32:07 – 3:36:29

    How AI will make money?

  19. 3:36:29 – 3:41:01

    Big acquisitions in 2026

  20. 3:41:01 – 3:53:35

    Future of OpenAI, Anthropic, Google DeepMind, xAI, Meta

  21. 3:53:35 – 4:00:10

    Manhattan Project for AI

  22. 4:00:10 – 4:08:15

    Future of NVIDIA, GPUs, and AI compute clusters

  23. 4:08:15 – 4:25:12

    Future of human civilization

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