Cerebras Systems (CBRS) said Thursday it is powering Ultrafast mode, a new service tier in OpenAI's application programming interface for GPT-5.6 Sol.
Ultrafast runs GPT-5.6 Sol at up to 750 output tokens per second and up to 14 times faster than Standard processing, the company said.
GPT-5.6 Sol Ultrafast answered the full 2500-question set for Humanity's Last Exam, a benchmark including graduate-level chemistry, economics and literature, in just over 11 hours, achieving comparable accuracy nearly seven times faster than Claude Fable 5, the company added.
Shares of Cerebras Systems were down nearly 14% in Thursday trading.
Price: $226.18, Change: $-35.89, Percent Change: -13.69%