The Ngen.exe (Native Image Generator) tool creates native binary images (files containing compiled processor-specific machine code) for assemblies. This improves CodeRush performance because it produces and installs binary images in the native image cache on the local computer. The runtime process can use native images from the cache instead of the just-in-time (JIT) compiler to compile the original assembly.
The "Improve performance with Ngen" notification in the Feature Advisor means that Ngen.exe is not installed on your computer. Click "Improve performance with Ngen" to run the Ngen Installer.
Ngen.exe requires administrative privileges. The system asks you for administrator privileges if you run Visual Studio without administrator rights.
Switch to the IDE/NGen Options settings and choose one of the following options:
Ask for every CodeRush update in the Feature Advisor notification (the default option).
Compile assemblies automatically after each CodeRush update.
Disregard the suggestion and never show it again.