I will explain a third time.

If you compile any C program with a C++ compiler (possibly making trivial changes to account for gratuitous language divergence) you will find, for reasons you note yourself, that it runs at exactly the same speed. NOT, let me emphasize here because this seems to be difficult to process, ever slower than C. Therefore, (try to follow this) C is never faster than C++.

So, it is at best foolish to insist that C can ever be faster than C. The falsehood is trivially exposed.

If you think that C++ is about OO gook and virtual functions, an education awaits. But not here.