GPT 5.6 Sol Ultra early benchmarks show major upgrade from GPT 5.5

GPT 5.6 Sol Ultra was tested against Fable 5 Max on a 6M-token codebase and 900K-token subsystem. Early users report it is 'very good' and 'a major upgrade' from GPT 5.5, with a 1.5x speed mode and increased autonomy.