c# - Should I use byte or int?

Question

I recall having read somewhere that it is better (in terms of performance) to use Int32, even if you only require Byte. It applies (supposedly) only to cases where you do not care about the storage. Is this valid?

For example, I need a variable that will hold a day of week. Do I

int dayOfWeek;

or

byte dayOfWeek;

EDIT: Guys, I am aware of DayOfWeek enum. The question is about something else.

Answer 1

Usually yes, a 32 bit integer will perform slightly better because it is already properly aligned for native CPU instructions. You should only use a smaller sized numeric type when you actually need to store something of that size.