🧠 GPT‑4 Series
- GPT‑4o – Released May 2024 as the flagship omnimodal model (text, image, audio) and replaced GPT‑4 in ChatGPT by April 30, 2025 .
- It even generates images natively, replacing DALL‑E 3 in March 2025 .
- GPT‑4.5 (“Orion”) – Debuted February 27, 2025; available to Plus and Pro users via API .
- Claims ~20% better performance, fewer hallucinations .
- GPT‑4.1, GPT‑4.1 mini, and GPT‑4.1 nano – Rolled out around April 2025 .
- GPT‑4.1 brings a massive 1‑million token context window, top-tier coding, instruction-following skills .
- “Mini” becomes default for free-tier users; “Nano” still API-only .
🔍 O‑Series: Reasoning-Focused Models
These models are powerhouse thinkers—designed to reason deeply and logically.
- o1 – Released December 2024; first reasoning-focused GPT .
- o3 Series:
- o3‑mini – Launched January 31, 2025 .
- o3 and o4‑mini – Released April 16, 2025. o4‑mini is a lighter, image-capable sibling of o3-mini .
- o3‑pro – Dropped June 10, 2025; billed as the most capable model yet—best reserved for challenging tasks where accuracy matters .
🧩 Quick Comparison: Which Model Should You Use?
| Model | Strengths | Ideal Use Cases |
| GPT‑4.1 | Vast context window, coding, instr-following | Complex conversations, long docs |
| GPT‑4.5 | Enhanced accuracy, fewer hallucinations | Precision-heavy tasks, deep technical work |
| GPT‑4o | Versatile multimodal (text, audio, image) | Creative, multi-format interactivity |
| o3‑pro | High-level reasoning, most reliable | Research, troubleshooting, technical demands |
| o4‑mini | Image-capable reasoning in light package | Fast image+text workflows |
Summary
The crown jewels right now are:
- GPT‑4 Series: GPT‑4o → GPT‑4.1 → GPT‑4.5
- O‑Series: Transitioning from o1 → o3‑mini → o4‑mini → now o3‑pro- the top reasoning model.
Let me know if you want to dive into context windows, pricing, APIs—or get fired up for your next power user strategy! 💪