▲ 16 r/ChatGPTPro
As is well known, a few days ago, GPT 5.4 Pro suddenly began thinking less and responding faster, showing a significant decline in performance in some areas, while in others it might have appeared to improve. It now appears that this phenomenon was caused by GPT 5.4 Pro being silently rerouted to GPT 5.5 (Pro). Based on my testing, it has now returned to its original state.
GPT 5.5 Pro still exhibits reduced reasoning and faster responses. Is this due to changes in the underlying model, or simply a reduction in the effort put into reasoning? I’ve noticed they’ve added a section inviting users to provide feedback.
u/ArchMeta1868 — 20 days ago