Performance question : Is it worth it to check before I set?

Questions & Answers
1

So I have this below. If I am doing an operation like this is it generally considered a good practice to “gate” the variable assignment with an if to avoid just continually assigning that variable while in the loop?

while (isMoving) {
	ATBgov.ATBspeed = loweredSpeed;
	yield return null;
}

Would it be better to add a line in there below?

if (ATBgov.ATBspeed != loweredSpeed) ATBgov.ATBspeed = loweredSpeed;

3

General rule of optimization: do not optimize if you’re not having performance problems. If you’re having performance problem, then figure out where and then fix it instead of optimizing everything.

2

NOTE: YOU CANNOT COMPARE FLOATS TO FLOATS SAFELY AS WAS DONE IN THE QUESTION
THIS IS A GENERAL ANSWER THAT IF STATEMENTS ARE BETTER. FLOATS SHOULDNT BE IN IF STATEMENT COMPARISIONS SO IT DOESN’T APPLY.

Yes its good practice.

Checks have a pretty low impact.

Things inside the if statements will at best probably be as efficient.

If that assignment was…
copying one array to another
finding a game object in a scene
calling a component through getcomponent
etc

You’d want to avoid doing those every frame, copying a hundred array variables 50 times a second is way slower than doing an if check 50 times.

Since almost nothing is faster than a if checks you if check.