Codex app on Windows became extremely slow today even in /fast mode
OpenAI Developer Community
March 9, 2026
Hi team, I’d like to report a performance issue with the Codex app on Windows.
Starting today, Codex has become extremely slow for me. A single response can take more than 20 minutes, even for a small project.
My setup:
* Codex app on Windows
* Model: GPT-5.4
* /fast mode enabled
* Repository size: around 20 files
* Project is on a Windows path
What makes this unusual is that the same setup was working much faster before. The slowdown started suddenly today.
What I already checked:
* Opened a brand new thread
* Kept the task small
* /fast mode is already enabled
* The repo is very small, so this does not seem related to repo size
* Previously, the same Windows-path workflow was fast, so this does not look like a simple “Windows path is slow” issue
Observed behavior:
* Codex stays in “thinking” for a very long time
* Even simple prompts take 20+ minutes
* The issue happens in new threads as well, not just old conversations
Expected behavior:
* Small tasks in a small repo should return much faster, especially in /fast mode
Additional note:
* I checked the public status page, and it appeared operational when I looked, so this may be a model-specific or app-specific performance issue rather than a broad outage
Would the team be able to check whether there is any current latency issue affecting GPT-5.4 in the Codex app on Windows?
Thanks.
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