Math.Pow vs multiply operator (performance)

Question

Anyone knows if multiply operator is faster than using the Math.Pow method? Like:

n * n * n 

vs

Math.Pow ( n, 3 ) 

Answer 1

I just reinstalled windows so visual studio is not installed and the code is ugly

using System; using System.Diagnostics;  public static class test{  public static void Main(string[] args){     MyTest();     PowTest(); }  static void PowTest(){     var sw = Stopwatch.StartNew();     double res = 0;     for (int i = 0; i < 333333333; i++){         res = Math.Pow(i,30); //pow(i,30)     }     Console.WriteLine("Math.Pow: " + sw.ElapsedMilliseconds + " ms:  " + res); }  static void MyTest(){     var sw = Stopwatch.StartNew();     double res = 0;     for (int i = 0; i < 333333333; i++){         res = MyPow(i,30);     }     Console.WriteLine("MyPow: " + sw.ElapsedMilliseconds + " ms:  " + res); }    static double MyPow(double num, int exp) {     double result = 1.0;     while (exp > 0)     {         if (exp % 2 == 1)             result *= num;         exp >>= 1;         num *= num;     }      return result; } } 

The results:
csc /o test.cs

test.exe

MyPow: 6224 ms:  4.8569351667866E+255   Math.Pow: 43350 ms:  4.8569351667866E+255  

Exponentiation by squaring (see https://stackoverflow.com/questions/101439/the-most-efficient-way-to-implement-an-integer-based-power-function-powint-int) is much faster than Math.Pow in my test (my CPU is a Pentium T3200 at 2 Ghz)

EDIT: .NET version is 3.5 SP1, OS is Vista SP1 and power plan is high performance.