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Ask HN: OpenAI GPT-5 API seems to be significantly slower – is this expected?
We've observed that the OpenAI GPT-5 API is noticeably slower than GPT-4.1 and GPT-4o. Is this a known or anticipated issue?
- rickcarlino 1y agoThe conventional response to this seems to be "Lower reasoning effort". I have already tried this. Like you, I am seeing a 5x slowdown compared to GPT-4O. I have lowered reasoning effort all the way, set verbosity to lowest. Still not getting good results. https://bsky.app/profile/rickcarlino.bsky.social/post/3lvycsxu6k22c https://bsky.app/profile/rickcarlino.bsky.social/post/3lvycs...
- tlogan 1y agoOK - so we are not crazy. The official response seems to be: set reasoning to the lowest and service_tier to priority, and it should work as fast as GPT-4o. But that is not the case. They are probably still tuning it. Or maybe GPT-5 is not meant to be replacement for GPT-4o / GPT-4.1. Or this is going to be a new normal (slowest).
- unsupp0rted 1y agoI thought this was a Cursor problem. GPT-5 is extremely slow at output. It seems to speed up after a “cold start” though, which seems highly unlikely technically, but that’s what it feels like.