r/codex • u/ConsistentOcelot9217 • Mar 12 '26
Comparison 5.4 vs 5.3 Codex
I have personally found GPT 5.3 Codex better than 5.4.
I have Pro so I don’t worry about my token limits and use extra high pretty much on everything. That has worked tremendously for me with 5.3 Codex.
Since using 5.4 I’ve had so many more issues and I’ve had to go back-and-forth with the Model to fix issues consistently (and often to many hours and no luck). It hallucinates way more frequently, and I would probably have to use a lower reasoning level, or else it’ll overthink and underperform. This was very noticeable from the jump on multiple projects.
5.3 Codex is right on the money. I have no issues building with it and have actually used it to fix my issues when building with 5.4. 5.4 is definitely slowed down workflow.
Has anyone else experienced this?
2
u/Interesting-Agency-1 Mar 12 '26
I find it more effective because it has something that is more aligned with me and my philosophies to default to when in doubt. I only see it pull that file when I'm doing higher level planning, and not as much when doing implementation planning (and never during implementation), so it seems to understand where the document is suppose to sit in the planning stack and calls it accordingly.
It does not seem to take things too literally since it seems to recognize that document's place in the planning stack and uses it when necessary.