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[Performance] GPT-6 Sol tasks taking 40+ minutes to complete #47656
Description
What version of the Codex App are you using (From “About Codex” dialog)?
26.917.62051
What subscription do you have?
ChatGPT Plus
What platform is your computer?
Microsoft Windows NT 10.0.26200.0 x64
What issue are you seeing?
I'm seeing a significant performance regression when using GPT-6 Sol in the Codex app.
I normally use Codex for relatively straightforward coding tasks, such as fixing an issue, implementing a feature, or correcting existing code. I rarely give it very large plans or tasks that I would expect to take hours.
With GPT-5.6 Sol, comparable tasks usually took around 20 minutes. Since GPT-6 Sol became available, the same kind of work is often taking around 50 minutes, sometimes more than twice as long and occasionally close to three times as long.
This has happened in roughly 9 out of the 10 tasks I've tested with GPT-6 Sol.
The main symptoms I observe are:
- Codex sometimes appears idle from the user's perspective for several minutes.
- Conversation compaction can take a particularly long time.
- Some shell/tool commands finish almost immediately, but Codex may still wait for several minutes before continuing.
- The slowdown also happens on relatively simple coding tasks, not only complex ones.
- In most cases the task eventually completes successfully, but sometimes I have to stop the run and tell Codex to continue because it appears to remain stuck for too long.
I started noticing this immediately after GPT-6 Sol became available. So far, this behavior appears to be specific to GPT-6 Sol; I did not experience the same level of slowdown with GPT-5.6 Sol.
Simple conversational messages (for example, just saying hello) respond normally.
I have not noticed connection errors, reconnect messages, or other obvious network-related problems.
What steps can reproduce the bug?
- Open the Codex app on Windows.
- Select GPT-6 Sol.
- Open a normal software repository.
- Give Codex a typical coding task, for example:
- fix an existing bug,
- implement a small/medium feature,
- modify existing code,
- or make several related changes as part of one task.
- Let Codex work normally without interrupting it.
- Observe that the task frequently takes around 40–50+ minutes to complete.
- During the run, Codex may appear idle for several minutes, especially during conversation compaction or after commands that have already completed.
- Repeat with similar tasks.
In my testing, this happened in approximately 9 out of 10 GPT-6 Sol tasks.
For comparison, similar tasks with GPT-5.6 Sol generally completed in around 20 minutes.
Sometimes the GPT-6 Sol task eventually continues by itself, but on some runs I have to stop it and ask it to continue because it appears stuck for too long.
I have not observed connection errors or reconnect messages during these runs.
What is the expected behavior?
GPT-6 Sol should complete typical coding tasks within a reasonable amount of time and should not spend several minutes appearing idle after commands have already finished or during conversation compaction.
For tasks comparable to those I previously ran with GPT-5.6 Sol, I would expect execution time to be in roughly the same range, rather than increasing from around 20 minutes to approximately 40–50+ minutes in most runs.
If additional reasoning time is required, the app should still continue making visible progress instead of appearing stuck for several minutes.
Additional information
Environment:
- Codex App version: 26.917.62051
- Platform: Microsoft Windows NT 10.0.26200.0 x64
- Subscription: ChatGPT Plus
- Model affected: GPT-6 Sol
I have mainly noticed this since GPT-6 Sol became available.
I have not seen obvious network errors, reconnect messages, or similar connectivity issues while the slowdown occurs.
The behavior is reproducible across multiple normal coding tasks and does not appear limited to one specific repository or one unusually large task.
If useful, I can provide additional examples, screenshots, logs, or session details from affected runs. Possibly related to #31233 and #28077, but this report is specifically about a performance regression observed with GPT-6 Sol since its release, compared with GPT-5.6 Sol on similar coding tasks.
Activity
claudiomartinez123 commentedon Sep 24, 2026
Additional reproduction on the same Windows Codex App version 26.917.62051, but using GPT-5.6 Terra at Medium reasoning (not GPT-6 Sol).
Environment:
Observed today:
This may indicate that the performance regression is not limited to GPT-6 Sol. It is being observed with GPT-5.6 Terra Medium on the same 26.917.62051 Windows app build.
The user can provide screenshots showing the 32m34s run and the About dialog/version if useful.
ArtemB91 commentedon Sep 24, 2026
I'm seeing very similar behavior with Codex CLI v0.156.1 and GPT-6 Sol.
The slowdown is not consistent across all sessions.
Some GPT-6 Sol sessions work normally and feel fast, while others become extremely slow. In an affected session, even a very simple sequence can take a surprisingly long time. For example, Codex may run a couple of commands such as git diff, receive the output almost immediately, and then spend several minutes reasoning before taking the next action.
claudiomartinez123 commentedon Sep 24, 2026
Follow-up reproduction after updating the Windows Codex/ChatGPT Desktop app.
Environment:
Result:
Screenshot evidence is available showing both the About dialog for 26.917.71314 and the 21m14s completed run.
felixsc321-hub commentedon Sep 26, 2026
Update after additional testing:
GPT-6 Sol appears to have improved consistently in terms of execution speed compared with when I originally opened this issue.
I have now used it for at least 15 additional coding tasks, and the improvement has been noticeable. Tasks that were previously often taking around 40–50+ minutes are now generally closer to approximately 25–30 minutes in my testing, which is much closer to the performance I would normally expect for this type of work.
However, I would not consider the issue fully resolved yet.
The main remaining problem seems to be with relatively simple or narrowly scoped tasks. For example, when asking Codex to only change or fix one specific thing, GPT-6 Sol can still take roughly twice as long as GPT-5.6 Sol did for comparable simple tasks.
For longer or more complex tasks, the situation has improved substantially and the original regression is much less noticeable than before.
So, based on my testing:
For that reason, I would consider the original issue partially resolved/improved rather than completely fixed.
I also noticed from the other reports in this issue that similar slowdown behavior has been observed with other model/configuration combinations, including GPT-5.6 Terra, so there may still be a broader performance issue involved.
MiracleCrane commentedon Sep 28, 2026
Additional reproduction on Codex Desktop for Windows (not the CLI), observed on September 28, 2026. Installed Windows package version: 26.924.2738.0 (package version, not the About-dialog version).
With GPT-6 Sol, the app may work for several turns and then a follow-up stays in “Thinking” for minutes without a visible assistant message or tool call. It can also stall partway through an active task: Codex makes some progress, then stops producing visible progress and does not recover during the time I wait. I have had to stop those turns manually.
Restarting the desktop app helps temporarily, sometimes only for a few messages, before the behavior returns. In one affected existing conversation, I stopped the stalled GPT-6 Sol turn, switched that same conversation to GPT-5.6 Sol, and the next turn completed normally.
This is distinct from simply taking longer to finish a task: some turns appear to stop advancing entirely. I cannot tell from the UI whether the cause is model processing, a stalled response stream, or the desktop client. It would help if the app surfaced a stalled connection or request failure instead of continuing to display “Thinking.” I can provide affected thread IDs and diagnostics through a private feedback channel if needed.
CharryWu commentedon Sep 28, 2026
Uploaded thread:
01a0e2e2-7253-7351-ac38-bf4a530c1676The main thread stuck at end of task or during compacting window, stuck for >10min. I had to manually interrupt and call it to retry. And it posts no updates, just infinite progress bars. Upon retry, codex executes normally, spend only 1~2 min of each coding tasks.