On Tuesday, September 22, two major artificial intelligence companies, Anthropic and OpenAI, each released updated models designed for different use cases. Anthropic unveiled **Claude Opus 5.5**, which it claims is its most powerful publicly available model to date, matching the capabilities of its previous model, Fable 5.1. OpenAI, on the other hand, launched **GPT-6 Sol**, which it describes as a more cost-effective version of its high-end GPT-6 Astra model. While Anthropic emphasized the model's computational power, OpenAI focused on affordability and efficiency. Both models include an "effort" slider that allows users to adjust how much time the AI spends processing a request before responding. The slider ranges from the most cost-efficient (quick but less detailed responses) to the most intensive (slower but more thorough responses). Claude Opus 5.5 is available through Anthropic’s API, as well as through platforms like Amazon Bedrock, Google Cloud Vertex AI, and Microsoft Foundry. It is also accessible to users with Anthropic’s Pro, Max, Team, and Enterprise subscriptions, but not the free version. GPT-6 Sol is accessible via OpenAI’s API, in ChatGPT Work, and in Codex, but not yet in the standard chat mode of ChatGPT. In terms of pricing, both models charge based on **tokens**, which are small units of text used to measure input and output. Anthropic charges $4 per million tokens for input and $20 for output with Claude Opus 5.5, while OpenAI charges $2 and $10 for GPT-6 Sol. Anthropic claims that Opus 5.5 is 40% more cost-effective in real-world use than its predecessor, Opus 5. OpenAI reports that GPT-6 Sol makes about half as many factual errors as its previous model, GPT-5.6 Sol. Independent testing by **Artificial Analysis**, a platform that evaluates AI models under consistent conditions, found significant differences in performance and cost efficiency. At maximum effort, Claude Opus 5.5 scored 58 points, compared to 48 for GPT-6 Sol. Even at medium effort, Opus 5.5 outperformed Sol at maximum effort. In professional fields such as finance, legal, and engineering, Opus 5.5 showed a clear edge. However, these results reflect Anthropic’s service as a whole, including its fallback mechanism, which can redirect requests to older models if certain security filters are triggered. While GPT-6 Sol is significantly cheaper per token—about half the cost of Opus 5.5—it has some limitations. For instance, a task from Artificial Analysis’s test costs about $5.98 with Opus 5.5 at maximum effort, compared to just $1.06 with Sol, making Sol nearly six times more affordable. However, Opus 5.5 generates about four times as many tokens per task and is slower to start. At medium effort, Sol responds in about 2 seconds, while Opus takes around 20 seconds. Additionally, Sol produces 114 tokens per second, compared to 78 for Opus. For tasks where accuracy is critical—such as coding, legal analysis, or financial modeling—Opus 5.5’s higher cost may be justified by its superior performance. In contrast, for chatbots, customer service, or large-scale automation, GPT-6 Sol offers nearly the same performance at a much lower cost and responds much faster at lower effort levels. However, these results are from the early days after the models' launch, and performance differences may shift over time as both models are used more widely.