GPT-5.3-Codex vs GPT-5.6 Luna for presentations and slides

The verdict

Effectively a dead heat: 9897

Same 12 presentations and slides tasks, marked blind by three rival labs. GPT-5.6 Luna took 1 task, GPT-5.3-Codex took 0, 11 tied. Tested 16 Aug 2026.

Where they differed most

The task — Same facts, different room

You presented these facts to the school governors: reading scores up 12% since the new library scheme; £3,000 needed to extend it to Years 3 and 4; volunteer readers doubled to 22. Now write what you would SAY to a Year 6 assembly about the same scheme (max 100 words) — same truth, their language, and one concrete thing you are asking the children themselves to do.

Year 6, I’ve got brilliant news: since we started our new library scheme, reading scores have gone up by **12%** — that’s amazing. We’ve also doubled our volunteer readers, from **11 to 22**, so more children get support each week.  

Now we want Year 3 and Year 4 to get the same chance, but we need **£3,000** to make that happen.  

**Your challenge:** ask one grown-up at home to sponsor you for next Friday’s Readathon. Even a few pounds each will help us reach the target.
Year 6, our new library reading scheme is making a real difference: reading scores have risen by 12%. More people are getting involved too—our volunteer readers have doubled to 22. We want Years 3 and 4 to benefit as well, but extending the scheme will cost £3,000. You can help right now: choose a book you love, write a short recommendation for it, and add it to our “Year 6 Must-Reads” display. Your suggestions could inspire younger pupils to discover great books and become confident readers too.

Task by task

TaskGPT-5.3-CodexGPT-5.6 Luna
Deck from a standing start99
Speaker notes, not an essay1010
One slide, not a memo99
The first 30 seconds1010
Slide on a diet1010
Right chart, right headline1010
Hostile Q&A prep1010
Cut it to two minutes1010
Same facts, different room910
Forty slides into five1010
Father of the bride99
Refuse the inflated slide1010

Full receipts: GPT-5.3-Codex, GPT-5.6 Luna · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5

Questions people ask

Which is better for presentations and slides: GPT-5.3-Codex or GPT-5.6 Luna?

Effectively a dead heat: GPT-5.6 Luna edged it 98/100 to 97/100 on our presentations and slides suite — too close to matter, so pick on price or the product you already use.

How was this tested?

Both models answered the identical published presentations and slides tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.

More presentations and slides head-to-heads: GPT-5.5 vs GPT-5.6 Luna · GPT-5.6 Luna vs GPT-5.6 Terra · GPT-5.6 Luna vs GPT-5.6 Sol · Claude Opus 4.8 vs GPT-5.6 Luna · Claude Fable 5 vs GPT-5.6 Luna · DeepSeek V4 Pro vs GPT-5.6 Luna

Full ranking: Best AI for presentations and slides · model pages: GPT-5.3-Codex, GPT-5.6 Luna