Fable 5 Tops KernelBench, Hand-Writes CUDA for 18.7x Speedup

Fable 5 topped the KernelBench-Mega benchmark by autonomously hand-writing CUDA code on an RTX PRO 6000, achieving an 18.7x speedup. This milestone led Anthropic's co-founder to declare the beginning of a Recursive Self-Improvement (RSI) loop.

2026-07-06 ~ 2026-07-07 · 2 related posts

• Fable 5 Tops KernelBench, Potentially Sparking an RSI Loop — manubfr · 2026-07-06
• Fable 5 Hand-Writes CUDA for 18.7x Speedup; Anthropic Co-Founder Declares RSI Loop Begun — 新智元 · 2026-07-07