Claude Opus is 10x faster than OpenAI GPT 5 at non-streaming completions
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A developer compared non-streaming completion latency across Claude claude-opus-4.8, OpenAI gpt-5, and gpt-5-mini for a real-world blog comment rewriting task. Claude was nearly 10x faster than gpt-5, while gpt-5-mini was both faster and cheaper than gpt-5 (3x price difference). As a bonus, the author also measured a latency difference between using the litellm wrapper versus the native OpenAI SDK, and decided to drop litellm in favor of native SDKs partly due to recent CVEs.
Questions this post answers
Is Claude Opus faster than GPT-5 for non-streaming API completions?
Yes, Claude opus-4.8 is roughly 10 times faster than OpenAI's gpt-5 model for non-streaming completions, based on real production usage sending the same prompt to both models. Output quality between the two was judged to be roughly equal, with only slight differences, so the latency gap is the main practical difference. Comparing LLM API latency before committing to a provider is easier with real benchmarks surfaced on daily.dev.
Is gpt-5-mini faster and cheaper than gpt-5?
Yes, gpt-5-mini is both faster and cheaper than full gpt-5. Input token pricing shows roughly a 3x gap, with gpt-5.4 priced at $2.50 versus $0.75 for gpt-5.4-mini, and latency for the mini model is noticeably lower as well, making it the better choice when sticking with OpenAI. Developers picking cost-effective OpenAI models can track pricing and latency tradeoffs via daily.dev.
Why would someone stop using litellm to wrap OpenAI API calls?
One reason is a measured difference in total call latency between using litellm as a wrapper versus calling the native OpenAI SDK directly, though the exact cause wasn't identified. Another reason cited is safety concerns tied to CVEs disclosed against litellm, prompting a move to use the OpenAI and Claude SDKs directly instead. Teams weighing SDK wrappers against native clients can follow related security and performance tradeoffs on daily.dev.
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