Ask HN: OpenAI GPT-5 API seems to be significantly slower – is this expected?

4 points by tlogan 1y ago ↗ HN

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?

2 comments of 3

[ 3.4 ms ] story [ 15.5 ms ] thread

rickcarlino 1y ago ↗

The 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/3lvycs...

unsupp0rted 1y ago ↗

I 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.