constexpr and performance result

Hi Why constexpr in function giving extremely high performance when i compare to plain function ?

example:

Code:constexpr auto fib_constexpr(unsigned int n) -> unsigned int {
return (n <= 1) ? n : fib_constexpr(n - 1) + fib_constexpr(n - 2);
}

auto fib_normal(unsigned int n) -> unsigned int {
return (n <= 1) ? n : fib_normal(n - 1) + fib_normal(n - 2);
}this constexpr function giving whole different result in performance

Thank You for answer.