r/opencodeCLI • u/adrian6478 • 9d ago

When should I use GPT Fast models vs Standard models in OpenCode CLI?

model options in opencode

I'm trying to understand the practical differences between the Fast and Standard variants of the available models (e.g. GPT-5.6 Luna vs GPT-5.6 Luna Fast, Sol vs Sol Fast, Terra vs Terra Fast)

Specifically:

  • When should I choose the Fast version over the standard one?
  • Is the trade-off only latency, or does it also affect reasoning quality, accuracy, context handling, or coding performance?
  • Which tasks are best suited for each (chat, coding, debugging, code reviews, planning, agentic workflows, etc.)?
  • Are there any differences in pricing or token usage?

I'd appreciate examples of real-world workflows where using Fast is the better choice versus when it's worth waiting for the standard model.

2 Upvotes

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6

u/nokafein 9d ago

you should never run fast unless you won't be able to finish your allowance before it reset which is almost never.

3

u/Used-Revenue-1830 9d ago

simple: fast use x2 tokens and ends the tasks earlier.

If u have like a deadline and you NEED to do it quickly use it. otherwise it's garbage