Microsoft will bring Phi Silica to the Windows runtime this quarter as part of Copilot, according to Microsoft's head of Windows devices, who presented on Monday at CES 2025 in Las Vegas. Microsoft debuted Phi Silica at its Build conference in Seattle last May, showing off the Small Language Model (SLM) that's meant to complement its Large Language Model (LLM) that runs in the cloud. Phi Silica paves the way for a local version of Copilot to run on Windows PCs. Typically, LLMs are faster and more accurate than SLMs. However, they need to run in the cloud and can require expensive subscriptions for full access. On the other hand, SLMs can run AI chatbots and other AI-driven applications on a local PC, but they're less sophisticated and they require NPUs that provide local AI capabilities for PCs, which can ensure privacy and prevent information from leaking to the cloud.

In 2023, Microsoft was a big believer in large language models, running in the cloud. At Microsoft Build, the company launched Phi Silica, a small language model designed to run specifically on the NPUs in new Copilot PCs. In April, Microsoft announced Phi-3-mini, a model small enough to run on a local PC. Phi Silica is a derivative of Phi-3-mini, designed specifically to run on the Copilot PCs that Microsoft announced Monday. Most interactions with AI take place in the cloud; Microsoft's existing Copilot service, even on your PC, talks to a Microsoft remote server.