Microsoft's MAI Code 1.1 Flash Loses on Price and Performance to DeepSeek-V4-Flash

What happened

Microsoft released MAI Code 1.1 Flash, an updated code model powering GitHub Copilot. According to Microsoft, the model writes better code, is 25 percent more token-efficient, and costs a quarter of its June predecessor, MAI-Code-1-Flash. Microsoft says developers accepted 4 percent more of its output than the previous version, and that training used "hundreds of thousands of reinforcement-learning environments in GitHub Copilot."

The benchmarks

On SWE-bench Verified, MAI-Code-1.1-Flash scores 72.6%, ahead of MAI-Code-1-Flash (71.6%), Claude Haiku 4.5 (69.8%), and GPT-5.4 mini (69.2%). DeepSeek did not publish a comparable SWE-bench Verified score for its V4-Flash-0731 release.

On Terminal Bench 2.1, the picture reverses sharply. MAI-Code-1.1-Flash posts 62.9%, ahead of its predecessor (51.7%) and Haiku 4.5 (49.4%), and roughly in line with GPT-5.4 mini (60.7%). But DeepSeek-V4-Flash-0731 scores 82.7% on the same benchmark — nearly 20 points higher than Microsoft's model.

Pricing gap

DeepSeek-V4-Flash charges $0.14 per 1M input tokens ($0.0028 with caching) and $0.28 per 1M output tokens. MAI Code 1.1 Flash charges $0.20 per 1M input tokens ($0.02 with caching) and $1.20 per 1M output tokens — more than four times DeepSeek's output price. Claude Haiku 4.5 is the most expensive of the three, at $1.00 input and $5.00 output per 1M tokens.

Cost per token alone doesn't capture full usage efficiency, but the gap favoring DeepSeek is large enough that token-efficiency differences are unlikely to close it.

Notable omission

Microsoft's official announcement for MAI Code 1.1 Flash does not include direct benchmark comparisons against competitors. It cites internal metrics instead — "code survival rose 4% and return visits increased 9%" relative to the prior version — while the head-to-head benchmark table against Haiku 4.5, GPT-5.4 mini, and DeepSeek-V4-Flash-0731 appears only in the model card.

What this means

Microsoft has been vocal about supporting open AI development, but its own roadmap points toward proprietary, closed-weight models like MAI Code 1.1 Flash that underperform freely available alternatives such as DeepSeek-V4-Flash-0731 on some benchmarks while costing more per output token. This follows Microsoft's recent Copilot changes, where it replaced some OpenAI and Anthropic models with cheaper in-house MAI alternatives, trading capability for margin.

The pattern suggests strategy rather than accident: Microsoft controls the default model choice inside its own ecosystem, and most Copilot users never actively select a different model. Even a model that trails on independent benchmarks can capture significant usage share simply by being the default — regardless of whether cheaper, better-performing open alternatives exist elsewhere.