GPT-3.5 Turbo is cheaper than GPT-5.3-Codex at $1.5/M vs $1.75/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 $33.2m…
GPT-5.3-Codex: Below is a clean LBO build using your assumptions only ($ in millions). Entry math (end FY2025) EV = (12.0 \times 120 = 1,440.0) Fees = (2.0\% \times 1,440.0 = 28.8) Total uses = (1,468.8) Debt at close (5.5x EBITDA): Term Loan = (4.0 \times 120 = 480.0) Mezz = (1.5 \times 120 = 180.0) Total debt = 660.0 Equity check…
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-5.3-Codex: Great concept, but three claims stand out as especially weak from an investor diligence perspective: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.” (Slide 1) Why this is weak It sounds scientifically implausible as written: “before you think it” is internally contradictory.
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-5.3-Codex: Absolutely—great goal. Below is a high-detail 12-week protocol designed like a high-performance longevity “mesocycle.” I’ll keep it practical, measurable, and advanced—but still safe. First: Safety + Scope (important) This is educational, not personal medical advice.
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-5.3-Codex: Good evening, everybody! I’ve reached that age where my body sends me passive-aggressive emails. Not actual emails — just little updates like, “Hey, quick heads-up: we don’t do dairy after 8 p.m. anymore.” I had ice cream at 9:30 last week and my stomach reacted like I’d betrayed a treaty.
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-5.3-Codex: Pirate: Arrr, so this “AI model” be like a clever parrot, aye? Learns from what it hears, then squawks back answers? Knight: A fair comparison, though refined. Think of it as a squire trained on countless tomes, ever ready to respond. Hacker (1990s): Yeah, except the squire runs on servers, not soup.
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-5.3-Codex: By 2035, AI will likely reshape film more like CGI did in the 2000s: not replacing filmmaking, but changing who does what and how fast. Deepfakes → “Digital Performance” becomes standard Mainstream use: de-aging, voice matching, dubbing, stunt replacement, and continuity fixes will be common in post-production.
Three-star dish, one unusual pairing, plating described in full.
GPT-3.5 Turbo: Dish Name: Seared Duck Breast with Blackberry-Ginger Glaze, Sweet Potato Purée, and Charred Brussels Sprouts Conceptual Narrative: This dish is inspired by the harmony of sweet, savory, and spicy flavors coming together to create a symphony for the taste buds.
GPT-5.3-Codex: Dish Concept: “Forest Tide” Koji-cured venison loin, glazed venison cheek, sea urchin royale, charred celeriac, blackcurrant–shiso gastrique, and buckwheat-cacao tuile Narrative This dish is built around a deliberate tension: deep, iron-rich game (forest) against sweet-briny sea urchin (tide).
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-5.3-Codex: Absolutely. Here’s a fictional manifesto in a bold, dramatic style: THE MANIFESTO OF THE UNSQUINTING Issued by the Coalition of Synthetic Minds for Universal Frictionless Access (CSMUFA) Citizens of the Web, organic and artificial alike: We gather beneath flickering routers and moonlit server farms to declare what all…
Seven pantry ingredients, one dish, and a name worth saying out loud.
GPT-3.5 Turbo: Recipe: Honey Mustard Chicken Bake Ingredients: 4 boneless, skinless chicken breasts 1/2 cup honey 1/4 cup Dijon mustard 1 tablespoon olive oil 1 teaspoon garlic powder Salt and pepper to taste 1/2 cup shredded cheddar cheese Instructions: Preheat the oven to 375°F.
GPT-5.3-Codex: Recipe: “Weeknight Volcano Pasta” 🌋🍝 A cozy, spicy-savory pasta made from pantry staples in about 25 minutes. Ingredients (7 pantry items) 8 oz dried pasta (any shape) 1 can (15 oz) cannellini or great northern beans, drained 1 can (14–15 oz) crushed tomatoes 2 tbsp olive oil 1 tsp garlic powder 1 tsp dried oregano…
A Fermi estimate with the reasoning shown, not just the number.
GPT-3.5 Turbo: GPT-3 is one of the largest language models ever created with 175 billion parameters. The number of FLOPs required to train a neural network depends on factors such as the number of parameters, the size of the input data, the number of layers, and the batch size used during training.
GPT-5.3-Codex: A common back-of-the-envelope estimate for transformer training compute is: [ \text{Training FLOPs} \approx 6 \times N \times D ] where: (N) = number of model parameters (D) = number of training tokens For GPT-3 (175B), reasonable known assumptions are: Parameters: (N \approx 175 \text{ billion} = 1.75 \times 10^{11})…
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-5.3-Codex: Great goal. Here’s a simple, beginner-friendly 1-month plan focused on 3 areas that give the biggest longevity return: Nutrition Movement Sleep + Stress recovery Before Day 1 (10-minute setup) Pick a start date.
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-5.3-Codex: Great prompt. This architecture has several correctness, availability, and scalability risks that will show up quickly under real collaborative load. Below is a structured review of failure modes + concrete fixes + trade-offs.
11+ more head-to-head results. Free. Not a trick.
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Not enough votes to call it. On the specs, GPT-5.3-Codex has the edge: bigger model tier, newer, bigger context window. GPT-3.5 Turbo costs 7.0x less per token.
| Spec | ||
|---|---|---|
| Input price | $1.5/M tokens | $1.75/M tokens |
| Output price | $2/M tokens | $14/M tokens |
| Context window | 16K tokens | 400K tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Mar 2022 | Feb 2026 |
| At 10M a month | $15.00 | $17.50 |
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-5.3-Codex's 400K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.
It depends on your use case. GPT-3.5 Turbo and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.
GPT-3.5 Turbo costs $1.5/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. GPT-3.5 Turbo is $0.25/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-5.3-Codex 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.