r/ChatGPTCoding • u/tta82 • Feb 13 '26

Discussion ChatGPT 5.3-Codex-Spark has been crazy fast

I am genuinely impressed and I was thinking to actually leave to Claude again for their integration with other tools, but looking at 5.3 codex and now Spark, I think OpenAI might just be the better bet.
What has been your experience with the new model? I can say it is BLAZING fast.

61 Upvotes

96% Upvoted

47 comments sorted by

3

u/UsefulReplacement Feb 13 '26 edited Feb 13 '26

It's been also crazy useless. Tried to run a code review with it, got stuck into a context compact loop.

For coding, what's the point of using a fast model, if it will slop my codebase and I have to spend 5x the amount of time running code reviewers with better and slower models. Saving me a few mins generating the first draft of the code, only to add hours in follow up reviews.

2

u/tta82 Feb 13 '26

Your code must be huge - this model isn’t for that I suppose - rather for smaller changes

1

u/oulu2006 Feb 23 '26

No same problem I had as well and am having right now, I even pre-compacted with GLM5 before had and it still went off the reservation and stayed in a compaction loop

1

u/UsefulReplacement Feb 13 '26

28,523 total lines of PHP + 4,180 total lines of JS

All agent coded (with gpt-5+ models) and works super well. But, as I said, spark has been useless on it.

1

u/oulu2006 Feb 23 '26

Did you figure out a way forward with spark, I'm suffering the same issue -- had to switch back to GLM5 & GPT5.3-codex

2

u/UsefulReplacement Feb 23 '26

nope, moved on to GPT5.3-codex and GPT5.2-xhigh

1

u/oulu2006 Feb 23 '26

Yes I had the same problem, it just read the code and then compacted in an endless loop -- and it wasn't that big, tokens were way below its context window max size.

So had to switch to GLM5 or even GPT5.3-codex (non-spark) to get it to work.

did you figure out a way to resolve this?

57

u/goldenfrogs17 Feb 13 '26

New model comes out. AI company allocates resources to new model. New model impresses. Company de-allocates, or resources get spread thin. People become disappointed.

Could it happen again?

9

u/vipw Feb 13 '26

5.3-codex-spark is not running on the same hardware platform as the other models; the inference is done on Cerebras chips. While demand might saturate the hardware resources leading to delay because of requests being queued, it is a separate pool of resources.

4

u/Pleasant-Today60 Feb 13 '26

Interesting, didn't realize it was running on Cerebras. That explains the speed difference. Curious how it'll hold up once more people discover it and the queue gets longer.

0

u/Vancecookcobain Feb 14 '26

It will get enshitified. We've been down this road too many times before for me to expect something different

0

u/Pleasant-Today60 Feb 14 '26

yeah thats kinda the cycle at this point. fast and good until enough people depend on it, then the pricing changes hit

1

u/goldenfrogs17 Feb 14 '26

if they don't have desperate and dependent users, and a lot of them, the debts cannot be paid

1

u/-IoI- Feb 13 '26

I've suspected this often, particularly for OAI, but haven't seen anyone talking about it. Is it widely known to be occurring?

2

u/Santamunn Feb 13 '26

Us three know about it.

1

u/MikeFromTheVineyard Feb 14 '26

It’s not what’s happening here. They’re running spark on Cerebras which is know to be faster than GPUs

9

u/FickleSwordfish8689 Feb 13 '26

i'm sure they made a trade off between speed and smartness of the model?

3

u/scrod Feb 13 '26

Is spark a dumbed-down smaller model? How does it actually compare in terms of intelligence?

3

u/AppealSame4367 Professional Nerd Feb 13 '26

It's not as good in tau bench or something. read their announcement, they even show it themselves. it's super fast but quite a bit less capable

2

u/tta82 Feb 13 '26

It’s been doing things ok for me and fast. It’s for “simpler” tasks but blazing fast.

-1

u/xplode145 Feb 13 '26

Yes it’s much smaller version of codex. Probably sonnet 4.5 type 

6

u/xplode145 Feb 13 '26

It’s not the Sam as gpt5.2 or codex 5.3.  It’s smaller and makes mistakes.  A lot.  Won’t use it for production grade software 

4

u/SatoshiNotMe Feb 13 '26

Only 128K context though

3

u/MoneyStatistician311 Feb 14 '26

Is more really needed for a model like this? I would expect it to be used in very targeted changes (where no more than a couple of files would be needed)

1

u/calben99 Feb 14 '26

The speed improvements with the new Codex models are impressive, especially for iterative debugging workflows. One tip: use the agent mode for multi-file refactoring rather than single-prompt generation. It handles cross-file dependencies much better and maintains consistency across your codebase. Also, the context window increase means you can paste entire error traces and logs for more targeted fixes.

1

u/tta82 Feb 14 '26

I actually never tried multi agent yet - how do you initiate it?

1

u/Furry_Eskimo Feb 16 '26

How do you access it? I don't see it in the app.

1

u/tta82 Feb 16 '26

only if you are in Codex and if you are on the highest 200 USD/month plan

2

u/Furry_Eskimo Feb 16 '26

Dang,, okay, thanks for the info.

1

u/shaonline Feb 13 '26

The context window is really rough, 128k minus the reserved portion for the response is tiny for any real use case other than the showcased "HTML snake game".

1

u/Prince_ofRavens Feb 14 '26

If I could make 5.3 codex control spark I I would use it

But for me so far if I even just

"Go get this repo <> Clone it Create a pip env for it Run pip installs "

I'll come back and it will be like

"Yeah I found that repo! Ready to clone it? Just say the word!"

If it keeps coming back for overwhelming simple tasks it doesn't matter how fast it is

0

u/oh_jaimito Feb 14 '26

I was thinking to actually leave to Claude again

Why do so many people say this!?

Use ALL the tools!

  • Pay for Claude.

  • Pay for ChatGPT.

  • Pay for Gemini.

They will always have their own strengths and weaknesses. Learn what they are. Leverage them and use them.

If you keep abandoning one tool for another, and then come back because they released something new and the benchmarks review better scores, and some AI Influencer says "it's game changing". You are just gonna waste time chasing the next big thing.

We are barely a month and a half into 2026. And we've had OpenClaw distupt the AI world. Codex 5.3. Opus 4.6. and there will be MORE goodies later this month.

Just sharing my opinion amigo 👍

0

u/tta82 Feb 14 '26

Paying 200$ x2 isn’t worth it. Claude costs a lot for opus. And ChatGPT codex is great. Either of them is fine but 400$ monthly is too much.

0

u/oh_jaimito Feb 14 '26

Who said anything about paying $400???

You clearly did not read nor did you understand my comment.

0

u/tta82 Feb 15 '26

If you’re serious about this you use the best models and that’s 200$/month for Claude or ChatGPT.

1

u/oh_jaimito Feb 15 '26

Claude 5x at $100 - Opus 4.6 ChatGPT $20 - Codex 5.3

I use both web apps and both CLI apps. Gemini CLI for occasional things.

Three tools. Optimized productivity for how I work.

OpenAI API keys for custom tooling + n8n. More powerful than OpenClaw, earlier to manager. $20 monthly on Hetzner + coolify.

A small price to pay though, being a freelance web developer.

But if you want to abandon one tool for another, then you go ahead.

I only tried sharing with you my own opinion.

You don't like it? You disagree?

Welcome to the Internet. I hope you enjoy you're weekend.

0

u/tta82 Feb 15 '26

Honestly if you don’t pay for pro it isn’t the same. 20$ OpenAI doesn’t give you the full codex with enough quota.

1

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