GPT-4.1 vs Phi-3.5-MoE Instruct

GPT-4.1

OpenAI

GPT-4.1, released by OpenAI in April 2025, is a large language model from the GPT-4 family optimized for coding, precise instruction following, and long-context tasks. It features a 1M token context window and native image understanding, with improved performance on tool-calling and web development benchmarks compared to GPT-4o. GPT-4.1 targets software development workflows, long-document analysis, and applications requiring accurate, instruction-adherent outputs.

Phi-3.5-MoE Instruct

Microsoft

Phi-3.5-MoE-instruct is a sparse mixture-of-experts model from Microsoft's Phi research team, released in August 2024 with 42 billion total parameters across 16 experts and approximately 6.6 billion active parameters per forward pass. The model applies Microsoft's small-data, high-quality training philosophy — developed across earlier Phi generations — to a MoE architecture, targeting reasoning quality comparable to much larger dense models at a fraction of the inference compute. Released under the MIT license, it was notable in the research community for demonstrating that MoE efficiency gains could be realized at smaller total parameter counts than typical large-scale MoE deployments.