[
    {
        "role": "user",
        "content": "when%20working%20in%20vs%20code%20with%20the%20github%20copilot%20models%20currently%20available%2C%20claude%20sonnet%204.6%20works%20well%20but%20is%20slow.%20of%20the%20other%20models%2C%20which%20work%20almost%20as%20well%20but%20faster%3F%20perhaps%20gpt%205.3%3F"
    },
    {
        "role": "assistant",
        "content": "If you're using GitHub Copilot in VS Code and you like Claude Sonnet 4.6 but find it slow, there *are* other models available that offer substantial speed improvements with comparable quality\u2014especially **GPT-5.3-Codex**. Here\u2019s a breakdown of what swaps might make sense, trade-offs, and tips for selecting faster models without losing much in output quality.\n\n---\n\n## What\u2019s Changed Recently\n\n- **GPT-5.3-Codex** was made *generally available* in GitHub Copilot in February 2026. It comes with up to **25% faster performance** compared to GPT-5.2-Codex in agentic/terminal-style coding tasks. ([github.blog](https://github.blog/changelog/2026-02-09-gpt-5-3-codex-is-now-generally-available-for-github-copilot/?utm_source=openai))  \n- **Claude Sonnet 4.6**, released mid-February 2026, also brings performance improvements\u2014especially in real-world/long-context settings. It\u2019s more capable than Sonnet 4.5 and is the default Sonnet model in many use cases. ([itpro.com](https://www.itpro.com/technology/artificial-intelligence/anthropic-promises-opus-level-reasoning-claude-sonnet-4-6-model-at-lower-cost?utm_source=openai))  \n- GitHub Copilot supports a range of models from OpenAI, Anthropic, Google etc., making side-by-side testing possible. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))\n\n---\n\n## How GPT-5.3-Codex Compares to Sonnet 4.6\n\n| Factor | GPT-5.3-Codex | Claude Sonnet 4.6 |\n|---|---|---|\n| **Speed in typical use** | Up to ~25% faster than GPT-5.2-Codex, especially in agentic workflows and when used in terminals or long tool-driven tasks. ([github.blog](https://github.blog/changelog/2026-02-09-gpt-5-3-codex-is-now-generally-available-for-github-copilot/?utm_source=openai)) | Good improvements over Sonnet 4.5, but not explicitly advertised as being this much faster in all settings. ([itpro.com](https://www.itpro.com/technology/artificial-intelligence/anthropic-promises-opus-level-reasoning-claude-sonnet-4-6-model-at-lower-cost?utm_source=openai)) |\n| **Quality trade-off** | Slightly better in benchmark metrics (Terminal-Bench etc.), especially when speed matters more than deep reasoning. ([claude5.ai](https://claude5.ai/blog/claude-sonnet-46-vs-codex-53-developer-comparison?utm_source=openai)) | Still strong across the board; excels at reasoning over large code bases, long-context workflows, and maintaining consistency under pressure. ([aitoolbriefing.com](https://aitoolbriefing.com/comparisons/gpt-codex-vs-claude-sonnet-agentic-coding-2026/?utm_source=openai)) |\n| **Context window / long tasks** | Solid, though Sonnet 4.6 has advantages with large-codebase or 1-million token context in some settings. ([itpro.com](https://www.itpro.com/technology/artificial-intelligence/anthropic-promises-opus-level-reasoning-claude-sonnet-4-6-model-at-lower-cost?utm_source=openai)) |\n| **Cost** | Slightly cheaper for many inputs/outputs than Sonnet 4.6 in some comparisons; so speed + cost savings possible in certain workflows. ([benchlm.ai](https://benchlm.ai/compare/claude-sonnet-4-6-vs-gpt-5-3-codex?utm_source=openai)) |\n\n---\n\n## Other Fast Model Options in GitHub Copilot\n\nIf GPT-5.3-Codex doesn\u2019t serve your exact needs or isn't available in your plan, here are alternatives:\n\n- **Claude Opus 4.6 (fast mode, preview)**: Offers Opus-level power but with reduced latency in \u201cfast mode.\u201d If you can access the preview, it might be a strong option. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))  \n- **GPT-5-mini, GPT-5.1, GPT-5.2, and their Codex variants**: Earlier versions of Codex tend to have shorter response times, particularly on lighter tasks. They trade off reasoning depth or long-context capability. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))  \n- **Gemini 3 Flash / Gemini 2.5 Pro (Google)**: These are listed in the supported models; often faster in lighter or less complex prompts, though results may vary by task. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))  \n\n---\n\n## What to Try in VS Code\n\nHere\u2019s how you can experiment to find the fastest model that still meets your quality bar:\n\n1. **Open the model picker in Copilot**  \n   In VS Code, switch between \u201cAsk\u201d, \u201cEdit\u201d, \u201cAgent\u201d modes and try selecting different models (e.g. GPT-5.3-Codex vs Sonnet 4.6 vs faster Opus or mini variants).\n\n2. **Benchmark using your own workload**  \n   Run a couple of your everyday tasks\u2014autocompleting lines, refactoring, writing longer functions\u2014and compare response times *and* how much tweaking you have to do afterward.\n\n3. **Start with \u201cfast mode\u201d where available**  \n   Some models like Opus 4.6 offer a \u201cfast mode\u201d or lower-effort setting which trades a little depth for speed. Good for exploratory coding or small edits. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))\n\n4. **Check your plan-availability**  \n   Some models are only available on certain plans (Pro+, Business, Enterprise, etc.). If you don\u2019t see a model, that might be why. ([docs.github.com](https://docs.github.com/en/copilot/using-github-copilot/ai-models/supported-ai-models-in-copilot?utm_source=openai))  \n\n---\n\n## My Recommendation (Based on What You\u2019ve Stated)\n\n- Yes\u2014**GPT-5.3-Codex** is likely your fastest \u201calmost as good\u201d option. If your tasks are more standard: snippets, bug fixes, autocomplete, agentic pipelines\u2014it should feel noticeably snappier while staying high-quality.  \n- If you need strong long-context reasoning, maintain large codebases, or stay in highly detailed agent workflows, **Sonnet 4.6** might still win despite being a bit slower.  \n\n---\n\nIf you tell me a few example tasks you do regularly\u2014like writing boilerplate, refactoring, agent tasks, etc.\u2014I can point you to what model settings to pick in VS Code for *your* workflow, and maybe even benchmark those for you."
    }
]