Difference between .com program and .exe program in c programming language

Both .com and .exe program are executable program
but .com program execute faster than .exe program. All drivers are .com
program. .com file has higher preference than .exe 
For example:
Open the command prompt in window OS. (Type CMD in Run)
In the command prompt type notepad and press enter key you will get the notepad. Since it executes notepad.exe 

Repeat the same task but now first create