c# - Are static methods more efficient?

Question

In terms of memory and time, is it better to make a method static?

Answer 1

Usually yes, there is no need to pass the "this" reference. That reference is passed in the ECX register so there is no additional stack space required. The register is already set if you make the call from an instance method of the same class, there will be no savings at all. But it can help relieving the pressure on a x86 CPU core when the method is in another class, x86 doesn't have a lot of registers. Seeing a measurable perf improvement would be exceedingly rare.

I do religiously mark methods of a class that don't use instance members as static. I value the inherent contract provided by the static keyword: "this method does not mutate the object state."