Users see a chat window. Sometimes voice, sometimes images. But behind this familiar interface lie radically different architectures and capabilities.

Here are five key parameters that distinguish the top AI models in 2025:

1. Memory (Context Window)

This defines how much information a model can retain within a single conversation.

  • GPT-4o: 128k tokens (~300 pages of text)
  • Claude 3 Opus & Gemini 2.5 Pro: Up to 1 million tokens (~2,000 pages)
  • DeepSeek-VL Mini: ~8k tokens (~20 pages)

More memory enables greater context and reduces hallucinations, but it also demands more powerful hardware.

2. Specialization

Versatility doesn’t always mean depth. Each model has its strengths.

  • GPT-4o: A multimodal generalist with eyes, ears, and a voice.
  • Claude 3 Opus: An analyst, skilled at structuring data, summarizing content, and complex reasoning.
  • Gemini 2.5 Pro: An engineer, excelling at writing code, processing tables, and solving scientific problems.
  • DeepSeek: A lightweight model focused on core reasoning and inexpensive inference.

3. Cost

The price per million tokens (input/output) varies dramatically:

  • GPT-4o: $2.50 / $10.00
  • Claude 3 Opus: $15 / $75
  • DeepSeek (Mini): Can be run locally for the cost of inference.

A model’s price tag is always a compromise between speed, analytical depth, and your cloud bill.

4. Infrastructure and Deployment

How you run the model is a fundamental choice.

  • Claude, GPT, and Gemini operate in hyperscale data centers that cost over $100M to build.
  • DeepSeek-VL Mini, Mistral, and LLaVA can be run on a local machine with a consumer GPU like an RTX 3060.

For a business, this is a critical strategic decision: does your AI live in the cloud, or on your own servers?

5. Customization Potential

  • GPT-4o, Claude, and Gemini are effectively black boxes. Fine-tuning is not an option.
  • Open models like DeepSeek, LLaVA, and OpenChat can be adapted for specific tasks.

Fine-tuning, with costs starting around $50,000, has become a realistic and powerful tool for businesses needing specialized AI.

The Takeaway

Models that appear identical on the surface are vastly different under the hood. If you’re building a product, it’s critical to understand not only what a model can do, but also what it will cost, where it runs, and how deeply you can adapt it to your needs.