There's a feature called Lightweight Solution Load [https://docs.microsoft.com/en-us/visualstudio/extensibility/lightweight-solution-load-extension-impact https

There's a feature called Lightweight Solution Load [https://docs.microsoft.com/en-us/visualstudio/extensibility/lightweight-solution-load-extension-impact https://docs.microsoft.com/en-us/visualstudio/extensibility/...] which does seem to just lazily load projects. But even with that turned off, opening large solutions is vastly faster than in VS2015.