Do Static or Instance Methods Scale Better in .NET?

In .NET would there be issues to consider between a static method in a static class and an instance method in a regular class with respect to scalability? Is there going to be a "log jam" if many many calls are made to a static method in a class? Or is that not an issue. If so, would it be better to use an instance method? Something like a method like GetCustomers() that is called to retrieve