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# Sonnet 4.5
- URL: https://blog.brokk.ai/sonnet/
- Published: 2025-09-29T19:30:18.000Z
- Updated: 2025-09-29T19:30:18.000Z
- Description: We've gotten used to vendors changing multiple things at once with their flagship releases, but Anthropic is playing a more conservative game.
- Author: Jonathan Ellis
- Tags: Blog

Sonnet 4.5 is Sonnet 4, but smarter.

We've gotten used to vendors changing multiple things at once with their flagship releases, but Anthropic is playing a more conservative game. Sonnet 4.5 has the same pricing, the same context limits, and the same janky manual prefix cache as Sonnet 4\. But now it's smarter.

[Here's what difference that makes](https://brokk.ai/power-ranking?version=openround&score=average&models=flash-2.5%2Cglm4.5%2Cgp2.5-default%2Cgpt5%2Cq3c%2Csonnet4%2Csonnet4.5&ref=blog.brokk.ai). 

![](https://storage.ghost.io/c/f5/e4/f5e49182-2f16-4855-8727-fde7524e784f/content/images/2025/09/image-8.png)

Sonnet has narrowly reclaimed the flagship model coding crown from GPT-5\. (Opus 4.1 also beat GPT-5, but while Sonnet 4.5 is 2x as expensive as GPT-5, which can be a reasonable trade for Sonnet's speed advantage, Opus 4.1 is almost 10x as expensive, so I've left it out of the charts here. Of course you can [customize the charts yourself on the live page](https://brokk.ai/power-ranking?version=openround&score=average&models=flash-2.5%2Cglm4.5%2Cgp2.5-default%2Cgpt5%2Cq3c%2Csonnet4%2Csonnet4.5&ref=blog.brokk.ai).)

Interestingly, while Sonnet 4.5's price-per-token is unchanged, it uses those tokens more effectively, resulting in about a 40% improvement in real-world cost-effectiveness--almost closing the gap to Gemini 2.5 Pro.

![](https://storage.ghost.io/c/f5/e4/f5e49182-2f16-4855-8727-fde7524e784f/content/images/2025/09/image-9.png)

Finally, Sonnet remains the clear leader in speed, with no real competition in sight; it's even faster than Gemini 2.5 Flash. This is part of what makes Sonnet worth the price premium. 

![](https://storage.ghost.io/c/f5/e4/f5e49182-2f16-4855-8727-fde7524e784f/content/images/2025/09/image-10.png)

Now that both OpenAI and Anthropic have released their next-gen models, the competitive landscape is firming up again. What can we expect from Gemini 3?