If you experience a severe slowdown of your pc when you open visual studio on your pc and either of these instances pops up in the task manager:
Evented I/O V8 node
This happens when a visual studio finds a gulpfile.js or package.json in a project and automatically runs it and so starts, bower, npm etc. and downloads and runs
If you want to stop this behavior and want to control when what happens :
Open Tools -> Options
Select Projects and Solutions / External Web Tools
Uncheck all four paths
Or search for package restore in tools->options in vs2017 and set all to false.