MiniMax M2.5 vs. GPT‑5.3‑Codex‑Spark

MiniMax M2.5 is an advanced frontier model designed to deliver real-world productivity across coding, search, agentic tool use, and high-value office tasks. Built on large-scale reinforcement learning across hundreds of thousands of structured environments, it achieves state-of-the-art results on benchmarks such as SWE-Bench Verified, Multi-SWE-Bench, and BrowseComp. The model demonstrates architect-level planning capabilities, decomposing system requirements before generating full-stack code across more than ten programming languages including Go, Python, Rust, TypeScript, and Java. It supports complex development lifecycles, from initial system design and environment setup to iterative feature development and comprehensive code review. With native serving speeds of up to 100 tokens per second, M2.5 significantly reduces task completion time compared to prior versions. Reinforcement learning enhancements improve token efficiency and reduce redundant reasoning rounds, making agentic workflows faster and more precise. The model is available in both M2.5 and M2.5-Lightning variants, offering identical intelligence with different throughput configurations. Its pricing structure dramatically undercuts other frontier models, enabling continuous deployment at a fraction of traditional costs. M2.5 is fully integrated into MiniMax Agent, where standardized Office Skills allow it to generate formatted Word documents, financial models in Excel, and presentation-ready PowerPoint decks. Users can also create reusable domain-specific “Experts” that combine industry frameworks with Office Skills for structured, professional outputs. Internally, MiniMax reports that M2.5 autonomously completes a significant portion of operational tasks, including a majority of newly committed code. By pairing scalable reinforcement learning, high-speed inference, and ultra-low cost, MiniMax M2.5 positions itself as a production-ready engine for complex agent-driven applications.

GPT-5.3-Codex-Spark is a specialized, ultra-fast coding model designed to enable real-time collaboration within the Codex platform. As a streamlined variant of GPT-5.3-Codex, it prioritizes latency-sensitive workflows where immediate responsiveness is critical. When deployed on Cerebras’ Wafer Scale Engine 3 hardware, Codex-Spark delivers more than 1000 tokens per second, dramatically accelerating interactive development sessions. The model supports a 128k context window, allowing developers to maintain broad project awareness while iterating quickly. It is optimized for making minimal, precise edits and refining logic or interfaces without automatically executing additional steps unless instructed. OpenAI implemented extensive infrastructure upgrades—including persistent WebSocket connections and inference stack rewrites—to reduce time-to-first-token by 50% and cut client-server overhead by up to 80%. On software engineering benchmarks such as SWE-Bench Pro and Terminal-Bench 2.0, Codex-Spark demonstrates strong capability while completing tasks in a fraction of the time required by larger models. During the research preview, usage is governed by separate rate limits and may be queued during peak demand. Codex-Spark is available to ChatGPT Pro users through the Codex app, CLI, and VS Code extension, with API access for select design partners. The model incorporates the same safety and preparedness evaluations as OpenAI’s mainline systems. This release signals a shift toward dual-mode coding systems that combine rapid interactive loops with delegated long-running tasks. By tightening the iteration cycle between idea and execution, GPT-5.3-Codex-Spark expands what developers can build in real time.