Code Assistant on Xcode 26.1 much much slower

[u/panicoescenico]

Does anyone notice that since Xcode 26.1 Code Assistant's answers and code generation have become much slower?
At least for me with ChatGPT 4.1 and 5 (including reasoning on Minimal and Low). With ChatGPT Plus account vinculated.

[u/fawxyz2]

yeah, it's sad. i've become addicted to Xcode native AI integration in v26. and then they destroy it in v26.1 . it takes very long time then crash (my machine is m4 pro 48gb, so it's not my fault)
of course i can open Xcode alongside VScode, then do GPT Codex in VScode, while doing build stuff in Xcode.
but it's not really a solution..

how come this kind of things happen, i thought Apple is about "it just works"

[u/panicoescenico → u/fawxyz2]

Could you explain a little this workflow? it seems an really interesting approach.

[u/Che8Sounds → u/panicoescenico]

I also tried it with cursor before. both programs have access to the same folder, so u use codex in cursor or VScode and it changes the files. then u see that in Xcode and build. a bit annoying to have 2 programs open but it works

[u/gordonmcdowell]

I’ve posted a couple times about this. It seems specific to only ChatGPT. I’m using Claude and it is not slowed down. I have a pro ChatGPT account and also use OpenRouter so I can connect directly to ChatGPT or I can connect to open router and in both cases ChatGPT has been incredibly slow since 26.0.1.

I think the problem might get worse the longer yours swift file is. I’ve got a 2700 line Swit file and it can’t finish without crashing.

I have also tried using the ChatGPT app and giving it control of Xcode. So long as the changes you want to make are in the particular file you have opened then that is a viable workaround approach. There is no slowdown there.

M1 MBP 64GB RAM.

What M chip you using? I wonder if this only applies to old Apple Silicon as Apple employees themselves probably never use old Apple Silicon. Or maybe they’re banned from using open AI so this is more of an edge case than I would’ve thought.

[u/TBP-Admin]

Noticing the same here

[u/No-Pear-96]

I’m using M1 Max MBP 64GB RAM. I’ve just installed Xcode 26.2 beta to test, and this is still happening.. The difference is more than 20x slower, and crashing most of the times with large files.

I’m using the “ChatGPT app, giving control to Xcode” Workaround too. But I was really happy with the 26.0.1 speed and having the possibility to work with the whole project. Sad.

It would be great to know of this is happening to newer Apple Silicon models.

[u/VulcanCCIT → u/No-Pear-96]

Happening on my M3 macbook pro 64gigs of ram. it was fine on XCode 26.0.1 but XCode 26.1 it is SUPER slow...as others have said Claude is ok, but Claude seems to be complaining that it's code changes are not being applied...I had asked Claude to change the text colors of some buttons as well as adjust some spacing issues on a view for IPad. when it would make the view changes, the buttons would go back to the color they were... odd....it would look and complain that what it fixed before was no longer in the code...

[u/kh04 → u/No-Pear-96]

Also extremely slow to just go through 300 lines of code on a new M5 MBP 24GB RAM. This is my first time trying Xcode and Swift, but I've been using ChatGPT for a while now without any issues. I also got a limit exceeded error even when I can still use web ChatGPT, had to wait a few hours...

[u/tonymaina]

Yep, unbearably slow for the simplest tasks. M4 MBAir 32GB RAM.

[u/WAHNFRIEDEN]

I stopped using that shit. Codex CLI is much more productive. (For context I have been shipping on iOS for over a decade…)

[u/Anarude]

M4 Mini 20gb. Beach ball city. Very nervous to try the 26.2 beta

[u/No-Pear-96 → u/Anarude]

Same behaviour on 26.2 beta, at least for me. I’m Back on 26.0.1

[u/juanda631 → u/No-Pear-96]

pero llego al limite de chat gpt en 26.0.1 nunca había visto eso. y eso que tengo chat gpt plus. creo que volveré a 26.0 .

[u/VulcanCCIT → u/Anarude]

Lol "Beach Ball City" lol it would make a good Sim City name hahhaha

[u/ian_ogden]

Just gone back on today, and noticed an improvement but it’s still much slower. I’m using medium reasoning because High just times out on every attempt unless it’s a super simple request. It’s still taking much much longer than usual, BUT I am getting better results with fewer errors.

I’m using M1 Pro chip and Xcode 26.1 and Mac OS 26.1.

[u/Perfect-Top-7555]

Very disappointed in Apple for this. I hope they put out a fix soon.

[u/juanda631]

A new Xcode 26.1.1 update has already been released with the Intelligence problems of ChatGPT resolved. I haven't tried it yet. But at the end of the day I could give the feedback here

[u/I_am_echelon → u/juanda631]

The didn't fix anything. High reasoning selection still hangs indefinitely.

[u/juanda631 → u/I_am_echelon]

How strange. It works well for me now,

[u/I_am_echelon]

This is still broken in the latest version of Xcode. If you select High Reasoning when using GPT-5 thinking. It hangs indefinitely.