OpenAI Previews 'Ultrafast' Tier for GPT-5.6 Sol, Claims Up to 14x Speed Increase

OpenAI is previewing a new service tier called Ultrafast that runs its GPT-5.6 Sol model at significantly higher speeds than standard API access. According to OpenAI, the tier can process requests up to 14 times faster than normal, generating up to 750 output tokens per second.

Ultrafast is powered by Cerebras hardware and launches first through the OpenAI API. This marks OpenAI's most direct move yet to address latency-sensitive use cases with its flagship reasoning model rather than relying solely on smaller, faster variants.

What's changing

GPT-5.6 Sol is the top-tier model in OpenAI's GPT-5.6 family, which the company introduced in June alongside a balanced model called Terra and a speed-focused model called Luna. The full family reached broad availability in July across ChatGPT, Codex, and the API.

Ultrafast does not introduce a new model. It is a new serving infrastructure and pricing tier that lets developers run the existing Sol model with dramatically reduced latency. OpenAI has not disclosed pricing for the Ultrafast tier.

Target use cases

OpenAI says Ultrafast is designed for workflows where response speed matters as much as model capability, including:

• Voice applications
• Customer support
• Commerce
• Developer agents
• Financial research
• Security incident response

The company claims its own engineering teams have already used Ultrafast internally, citing examples like analyzing logs and traces during live incidents and compressing research cycles that previously required overnight runs into iterations completed within a single workday. These are OpenAI's own claims and have not been independently verified.

Limited access

Ultrafast is not broadly available. OpenAI says access is currently restricted to a select group of customers while it evaluates how the increased speed affects real-world products and while it builds out capacity. Interested businesses can join a waitlist by submitting details about their workload, latency requirements, and expected usage volume.

No timeline for general availability has been announced.

What this means

The Cerebras partnership signals OpenAI is willing to route its most capable model through specialized inference hardware rather than optimizing solely through model architecture changes. Cerebras chips are known for high-throughput token generation, and a 750 tokens/second claim — if it holds under real production load — would put Sol's effective speed well ahead of typical GPU-served frontier models, which often run in the tens of tokens per second range for large models.

The limited, waitlist-gated rollout suggests OpenAI is still validating cost and reliability at scale before committing to broad availability. For developers building latency-sensitive products — voice agents, real-time customer support, or trading tools — this could eventually remove the tradeoff between using a smaller, faster model and a larger, more capable one. But until pricing is disclosed and the tier moves out of preview, it's unclear whether Ultrafast will be economically viable for most use cases or remain a premium option for high-value enterprise workloads.