One input and one output without any back and forth. Not using for continuous conversation

Hello, I am using ChatGPT API to feed a prompt (70ish words) and use whatever response it gives back (400ish words). No conversation. I also don’t really care for latest broader knowledge. It is a very simple use: one input and one output without any back and forth. What model should I use? gpt-3.5-turbo-0125 or gpt-3.5-turbo-instruct?
Thank you so much for your help.

Yeah, I don’t care for chat history or previous interactions. Each input and its gpt output are treated completely independently from other inputs/outputs. So there shouldn’t be any difference in instruct vs 0125? If it’s a HUGE difference in speed for returning output of about 400ish words, that matters. Otherwise, I can just go with 0125 which is cheaper than instruct.

gpt-3.5-turbo-0125 is a chat model. Like ChatGPT.

gpt-3.5-turbo-instruct-0914 is a completion model. Like autocomplete on your phone.

If your output is a continuation of the input, gpt-3.5-turbo-instruct-0914 might be a better choice. If you’re gonna use it like chatgpt, gpt-3.5-turbo-0125 is gonna be a better choice.

One’s a bic razor, the other’s a razor blade. Which one should you use?

It depends on what you’re trying to do! But it should be fairly obvious if you try em on the playground, like _j linked.

Thank you to both of you. That made my understanding of models much better. And since I knew what to ask, I asked ChatGPT with added question “since gpt-3.5-turbo-instruct is 3 times more expensive than gpt-3.5-turbo-0125, can I use gpt-3.5-turbo-0125 for my scenario above”, ChatGPT answered it well suggesting that in my scenario above, both models would be fine since my requirements are simple and so I could go with cheaper gpt-3.5-turbo-0125.

I also played in playground and both models were successfully returning a good response as per my needs.