Calling a method on an object a bunch of times versus constructing an object a bunch of times

Question

I have a List called myData and I want to apply a particular method (someFunction) to every element in the List. Is calling a method through an object's constructor slower than calling the same method many times for one particular object instantiation?

In other words, is this:

for(int i = 0; i < myData.Count; i++)
    myClass someObject = new myClass(myData[i]);

slower than this:

myClass someObject = new myClass();
for(int i = 0; i < myData.Count; i++)
    someObject.someFunction(myData[i]);

?

If so, how much slower?

Answer 1

The former approach might result in significant increase of your process working set. It also might put a memory pressure on Windows, causing other apps to be swapped out to the disk.

Also, it will put a lot of pressure on the CLR garbage collector, since each new object you create will be tracked for collecting.

How much slower it will be depends a lot on the size and the number of objects you are creating.