VSGD is a new is a tool to help diagnose graphics rendering and performance issues in DirectX apps which has been made available with Visual Studio 2013 Update 3 RC (Download)
So where do you find VSGD
VSGD is a new option under the DEBUG->Graphics->Start Diagnostics menu or you can quick access the feature by pressing Alt+F5 on the current solution or an exe in VS.
More details on VSGD
A must read for Graphics Enthusiast is Graphics Diagnostics Overview this provides a high level summary of what's new in VSGD in VS 2013 Update 3 RC but here a quick list of new features.
1. New Visual Studio Graphics Analyzer IDE: A dedicated space for analyzing graphics frames
2. Shader Edit and Apply: View the impact of shader code changes in a captured log without re-running the app
If you prefer to watch these features in action, check out the latest Channel9 video I will also be doing some additional blogs about the Visual Studio Graphics Analyser and Visual Studio PixelShader