# Reasoning Revolution: From OpenAI o1 to DeepSeek-R1 — Test-Time Compute and the Rebirth of Chain-of-Thought

> Source: https://sukruyusufkaya.com/en/learn/llm-muhendisligi/reasoning-models-o1-deepseek-r1-test-time-compute
> Updated: 2026-05-13T11:59:44.371Z
> Category: LLM Mühendisliği
> Module: Module 17: Reasoning Models — o1, DeepSeek-R1, Test-Time Compute
**TLDR:** 2024-2026 LLM frontier: reasoning models. OpenAI o1 (Sept 2024), DeepSeek-R1 (Jan 2025) revolution. Test-time compute scaling (Kaplan's new dimension), chain-of-thought intensification, hidden reasoning tokens (o1) vs visible (R1), RL training reasoning patterns. AIME, MATH benchmark revolution, GPT-4 → o1 90% accuracy jump.