Fastest way to convert a list of objects to csv with each object values in a new line

Use servicestack.text

Install-Package ServiceStack.Text

and then use the string extension methods ToCsv(T)/FromCsv()

Examples:
https://github.com/ServiceStack/ServiceStack.Text

Update:
Servicestack.Text is now free also in v4 which used to be commercial. No need to specify the version anymore! Happy serializing!