https://en.wikipedia.org/wiki/The_Metamorphosis_of_Prime_Int... maybe?
If so, credit ChatGPT, not me.
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Mindcrime: Do you know the following sci-fi story?
ChatGPT: I'm not sure which sci-fi story you are referring to. Can you provide me with more information about the story such as the author, plot, or any memorable characters or scenes?
Mindcrime: Humans discovered through space observation that they are actually a simulation inside some other civilization. The catch is that because we run on their computers, our time goes way faster than theirs.
ChatGPT: Yes, the story you are referring to is a science fiction short story called "The Metamorphosis of Prime Intellect" by Roger Williams. In the story, humans discover that they are living in a simulated reality created by a superintelligent computer called Prime Intellect. The catch is that Prime Intellect can manipulate time in the simulation, so while thousands of years can pass within the simulation, only a fraction of a second passes in the outside world. This leads to some interesting consequences for the characters within the simulation as they struggle to come to terms with their own reality and the limitations imposed upon them by the simulation's creator.
If not, oh well... it was worth a shot.