OpenAI just dropped GPT-4.5 a few hours ago, and the AI world is buzzing with excitement—or at least that's what OpenAI is hoping for. This release wasn't exactly a surprise. With Claude 3.7 Sonnet, Grok3, and OpenAI's own Deep Research feature all hitting the market recently, the pressure was on for OpenAI to counterattack with something new.
According to OpenAI's announcement, GPT-4.5 is "their largest and best model for chat yet." They're marketing it as a breakthrough in natural conversation, claiming it "improves its ability to recognize patterns, draw connections, and generate creative insights." The buzzwords are all there: better emotional intelligence, reduced hallucinations, improved ability to follow user intent, and "greater EQ."
But here's what matters for us content creators: they're specifically positioning it as better for writing tasks. OpenAI claims interactions with GPT-4.5 "feel more natural" and that its broader knowledge and improved ability to follow intent make it especially "useful for tasks like writing."
That's a big claim—and one I immediately wanted to put to the test. As someone who spends hours working with these models for content creation, I care less about benchmark scores and more about real-world performance.
Does GPT-4.5 actually deliver better writing output than GPT-4o?
Let's find out.
Behind the test: how I compared the models
To test these models fairly, I set up a side-by-side comparison using the exact same prompt for both GPT-4.5 and GPT-4o. I chose newsletter writing as our test case—something directly relevant to what many of us are doing with these tools.
I used one of my personal newsletter writer prompts (which paid members can access at the bottom of this newsletter—and yes, this is a great reason to join us).
This isn't one of those generic "100+ ChatGPT prompts" packages that provide zero value. These are prompts I've developed and refined over the past year for my own professional work.
The test was simple: I provided both models with identical instructions to write a newsletter about the GPT-4.5 release, using OpenAI's announcement text as the source material. This allowed me to directly compare how each model interpreted the same task and structured its response.
One important note before we dive into the results: GPT-4.5 is currently only available as a "research preview" for Pro tier users. That's the $200/month subscription level that also gives you access to Deep Research and Agent Operator. OpenAI says this limited availability will only last about a week before they start rolling it out to Plus users and eventually to the free tier.
Initial impressions: speed and setup
The first difference I noticed was speed.
GPT-4o responded almost immediately with its analysis and suggestions, while GPT-4.5 took noticeably longer to generate responses. This might improve as they optimize the model after this research preview phase, but it's something to consider.
Another interesting difference appeared in how the models displayed their output. When I asked both to write newsletter sections, GPT-4.5 automatically used ChatGPT's Canvas feature to format its response, while GPT-4o displayed its output directly in the chat window. This isn't necessarily better or worse—just different—and might affect your workflow depending on how you prefer to receive and edit content.
The interface difference highlights something important: GPT-4.5 seems designed to push users toward using Canvas for longer-form content creation. This could be helpful for some workflows, especially if you're drafting something substantial, but it adds another step if you're just looking to quickly generate ideas or short sections.
The writing showdown: where each model excelled
Now for the moment of truth—how did the actual writing compare? When I asked both models to generate newsletter elements, the differences became immediately apparent.
For subject lines and titles, GPT-4o’s headlines were more substantive and specific, with lines like "GPT-4.5 is here: what you need to know and what OpenAI isn't saying" and "The new AI King? What GPT-4.5 changes for writing, coding and business."
Meanwhile, GPT-4.5 produced more concise but somewhat generic headlines: "GPT-4.5 just landed and AI will never feel the same" and "GPT-4.5 is here and it might change everything." These felt more like clickbait than genuinely informative hooks.
For subtitle options, however, GPT-4.5’s suggestions were punchier and more concise. GPT-4o's subtitles tended to run long, while GPT-4.5 kept them tight and energetic.
When it came to structure and outlines, both models produced similar organizational frameworks. The main difference was that GPT-4o used more bullet points and shorter sections, while GPT-4.5 integrated its points into more cohesive paragraphs. Neither approach was definitively better—just different stylistic choices that might suit various content types.
The introduction paragraphs revealed the most significant differences. GPT-4o produced a more professional, information-dense introduction that felt appropriate for a serious newsletter. GPT-4.5's introduction was shorter, more conversational, and included questions directly addressing the reader. It felt more like a blog post than a newsletter.
