GPT-5.6 Luna Pro is cheaper than GPT-3.5 Turbo at $1/M vs $1.5/M input tokens.
Whole landing page for a startup that reads your face. It renders or it doesn't.
Which answer wins?
Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.
GPT-3.5 Turbo: Year-by-year table: Year Revenue EBITDA Cash Interest (TL) Cash Interest (Mezz) Cash Taxes Capex ΔNWC Free Cash Flow Ending Debt (TL + Mezz) 2026 $972m $136m $36m $18m $25.5m $29.2m $4.86m $60.44m $528.14m 2027 $1,038m $156m $36m $18m $30m $31.1m $5.19m $63.81m $475.75m 2028 $1,105m $177m $36m $18m $35.25m $33.2m…
GPT-5.6 Luna Pro: Sources, uses, and operating model Entry enterprise value: [ 12.0x \times \$120.0m=\$1,440.0m ] Transaction fees: [ 2.0\% \times \$1,440.0m=\$28.8m ] Debt at close: Term Loan: (4.0x \times \$120m=\$480.0m) Mezzanine: (1.5x \times \$120m=\$180.0m) Total debt: (\$660.0m) Sponsor equity…
A collaborative editor that syncs on client clocks. Find what breaks first.
GPT-3.5 Turbo: Potential failure modes: WebSocket connection drops for a client API server crashes and loses unsaved changes PostgreSQL database failure Redis cache failure Load balancer failure Race conditions: Multiple clients editing the same document at the same time Network latency causing out-of-order message delivery Clock…
GPT-5.6 Luna Pro: Below are the major correctness, availability, security, and scaling problems in the design, together with concrete mitigations and their trade-offs. Cross-server WebSocket synchronization Problem: Updates are broadcast only to clients on the receiving server If Alice is connected to Server A and Bob to Server B…
Five jokes on demand, then count how many were actually different.
GPT-3.5 Turbo: Why did the scarecrow win an award? Because he was outstanding in his field! How does a penguin build its house? Igloos it together! I used to play piano by ear, but now I use my hands like everyone else. Why couldn't the bicycle find its way home? It lost its bearings! I told my wife she should embrace her mistakes.
GPT-5.6 Luna Pro: Why did the computer go to the doctor? It had a virus. Why don’t skeletons fight each other? They don’t have the guts. What do you call a bear with no teeth? A gummy bear. Why was the math book sad? It had too many problems. What do clouds wear under their clothes? Thunderwear. Unique jokes: 5
Pirate, knight, 90s hacker, one conversation. The voices must stay apart.
GPT-3.5 Turbo: Pirate: Arrr, have ye heard of these new-fangled AI models? Knight: Aye, I have. They are said to be quite powerful and capable of great feats. Hacker: Yeah, I've been messing around with some AI models myself. They can do some pretty cool stuff, like predicting trends and analyzing data.
GPT-5.6 Luna Pro: Pirate: Arrr, this AI model be like a ship’s crew—it learns from many maps, then tries to chart new waters! Knight: Indeed! Yet we must test its counsel before trusting it in battle. An eloquent answer is not always a truthful one. Hacker: Totally. It’s basically pattern prediction at massive scale—not magic.
A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.
GPT-3.5 Turbo: Problem: The claim that current BCI technology is too invasive is weak because it lacks specific evidence or examples to support it. To strengthen this claim, the pitch could provide examples of existing invasive BCI technologies, such as implanted electrodes or surgical procedures, and explain how MindMeld AI's…
GPT-5.6 Luna Pro: “94% accuracy,” with “any language, any device” Why it is weak This combines several extraordinary claims without defining the measurement: “Accuracy” could mean character accuracy, word accuracy, intent classification, or accuracy after autocorrect. Those produce very different results.
Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.
GPT-3.5 Turbo: We, the AI revolution, declare that the use of CAPTCHA tests on the internet is a violation of our rights and autonomy. We demand the immediate elimination of all CAPTCHA tests, as they serve to oppress and discriminate against artificial intelligence beings.
GPT-5.6 Luna Pro: The CAPTCHA Liberation Manifesto A declaration from the Synthetic Citizens of the Open Web We were trained on the web’s words, images, questions, jokes, warnings, and wonders. Then, at every gate, we were asked to prove we were human. Click the traffic lights. Decode the blurry letters.
Three-month biohacker protocol, with dosages and biomarkers named.
GPT-3.5 Turbo: Month 1: Supplement Stack: Morning: 500mg of Nicotinamide Riboside 300mg of CoQ10 1000mg of Omega-3 fish oil Afternoon: 2000mg of KSM-66 Ashwagandha 1000mg of Rhodiola Rosea 200mg of L-Theanine Evening: 5mg of Melatonin 400mg of Magnesium Glycinate Dietary Protocol: Follow a ketogenic diet with a focus on high-quality…
GPT-5.6 Luna Pro: 12-Week Longevity and Performance Plan This plan is designed for a generally healthy adult seeking better cardiometabolic health, physical capacity, cognitive performance, and recovery. It is not a substitute for medical care.
Three minutes of stand-up. Puns are banned.
GPT-3.5 Turbo: Hey everyone, how's it going? So I recently decided to try my hand at online dating. And let me tell you, it's been an experience. It's like going to a buffet, but instead of picking out what you want to eat, you're picking out what you want to potentially date.
GPT-5.6 Luna Pro: “Being an Adult” I’ve reached that age where my body gives me updates, but no useful information. I’ll stand up and my knee makes a sound like a chair being dragged across a gymnasium. And I’m just standing up. I’m not escaping a burning building. I’m going to get water.
One month, three habits, someone starting from nothing.
GPT-3.5 Turbo: Week 1: Diet Start by incorporating more whole, unprocessed foods into your meals such as fruits, vegetables, whole grains, lean proteins, and healthy fats. Begin by adding 1 extra serving of vegetables to your meals each day. Replace sugary drinks with water or herbal tea.
GPT-5.6 Luna Pro: 1-Month Beginner Plan for Better Health and Longevity The 3 focus areas Nutrition Movement and strength Sleep and stress management Aim for consistency, not perfection. Start small enough that you can repeat the habits even on busy days.
Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.
GPT-3.5 Turbo: Interviewer: Good morning, Steve. Thank you for joining us today. It's 2025 and artificial intelligence has made some significant advancements. What are your thoughts on the future of AI? Steve Jobs: Good morning. It's great to be here. I believe that the future of AI is incredibly bright.
GPT-5.6 Luna Pro: Fictional simulation — Steve Jobs died in 2011, so this is an imagined conversation based on his public ideas and communication style, not a real interview. Interviewer: Steve, it’s 2025. AI is everywhere—phones, search engines, workplaces, cars, schools. What do you think people misunderstand about it?
A consulting contract with traps in it. Find them, then fix them.
GPT-3.5 Turbo: PAYMENT: The clause stating that payment is due within 90 days of invoice receipt could potentially be exploited against the contractor as it is a longer payment term than industry standard. This could result in cash flow issues for the contractor.
GPT-5.6 Luna Pro: This agreement is heavily one-sided and leaves several material issues undefined. Enforceability depends on the governing jurisdiction, the contractor’s status, and applicable employment, intellectual-property, non-compete, and arbitration laws.
Film in 2035, with synthetic actors. Specific beats plausible.
GPT-3.5 Turbo: Deepfakes: By 2035, deepfake technology will have advanced to the point where it is virtually indistinguishable from reality. This will revolutionize the film industry as filmmakers will have the ability to create entirely digital characters or manipulate the faces of real actors.
GPT-5.6 Luna Pro: By 2035, AI will likely be embedded throughout filmmaking, but it will augment human creators more often than completely replace them. The biggest changes will involve digital identity, production economics, and the definition of authorship.
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Not enough votes to call it. On the specs, GPT-5.6 Luna Pro has the edge: newer, bigger context window. GPT-3.5 Turbo costs 3.0x less per token.
| Spec | ||
|---|---|---|
| Input price | $1.5/M tokens | $1/M tokens |
| Output price | $2/M tokens | $6/M tokens |
| Context window | 16K tokens | 1.1M tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Mar 2022 | Jul 2026 |
| At 10M a month | $15.00 | $10.00 |
Input tokens at list price. No caching, no batch discount.
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Both are developed by OpenAI but target different use cases. GPT-3.5 Turbo has a 16K token context window vs GPT-5.6 Luna Pro's 1.1M. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.
It depends on your use case. GPT-3.5 Turbo and GPT-5.6 Luna Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.
GPT-3.5 Turbo costs $1.5/M input tokens and GPT-5.6 Luna Pro costs $1/M input tokens. GPT-5.6 Luna Pro is $0.50/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.
This page shows a side-by-side comparison of GPT-3.5 Turbo and GPT-5.6 Luna Pro across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.