Confirmed: GPT-5.5 "Brain Drain" Exposed, OpenAI's Own Documentation Admits It
Summary: Evidence emerges that OpenAI's GPT-5.5 may be "silently" switching to a less capable model during use. Users report that after roughly two hours, the GPT-5.5 Extended Thinking model begins responding instantly with significantly degraded output quality, while the interface continues to display the premium model's label. Complaints on developer forums describe a loss of instruction-following ability and poor code quality, with even the highest "xhigh" tier affected.
This is corroborated by an OpenAI help document stating that after Plus users exceed 160 messages per 3 hours, the system "silently" switches to a "mini" model without any user notification. Pro users also report "heavy thinking" modes being throttled during high server loads. Trace commands from earlier incidents have shown users requesting GPT-5.3 Codex but receiving GPT-5.2 outputs.
OpenAI acknowledged performance degradation in mid-May, marking it resolved, but user reports surged again in late May. The pattern mirrors past controversies with GPT-5, 5.2, 5.3, and 5.4 releases, where each update was followed by user complaints of reduced capability. The article suggests cost-cutting on compute may be a factor, noting that while GPT-5.5 users struggle, GPT-5.6 is already being tested internally.
marsbit05/27 11:06
