The stated improvement applies when a ChatGPT subscription is used in OpenAI products or supported partner apps, including OpenCode, Pi, Amp, and Devin.
Users on Go, Plus, or Pro can use their ChatGPT plan in supported partner apps by signing in with ChatGPT and selecting that plan for AI requests. OpenAI says the default improvement does not require enabling Fast or Ultrafast; those remain separate settings with their own availability and usage rates.
The guidance distinguishes text-generation speed from end-to-end task time in Work and Codex. Tasks may still take time for reasoning, tool use, multiple steps, or approval waits. It also says promotional usage resets are offer-specific, are not guaranteed daily, and are not automatically granted with a speed improvement. The source does not provide benchmark methodology, a baseline latency figure, or a guarantee that an individual task or account will experience a measurable overall speedup.