Performance benchmark for using Math.Sin(...) and Math.Cos(...) vs accessing values from a precalculated sine wave array.

precalculatedTrig.cs

ModelHelper.InitialiseTrigonometry();

Random rand = new Random();

int count = 524288;
float[] randoms = new float[count];
float[] result = new float[count];

int[] mathTimes = new int[100];
int[] arrayTimes = new int[100];

for (int c = 0; c < 100; c++)
{
    for (int i = 0; i < count; i++)
        randoms[i] = (float)(rand.NextDouble() * 100 - 50);

    Stopwatch ss = new Stopwatch();
    ss.Start();

    for (int i = 0; i < count; i++)
    {
        var sin = Math.Sin(randoms[i]);
        var cos = Math.Cos(randoms[i]);
    }

    mathTimes[c] = (int)ss.Elapsed.Ticks;
    ss.Restart();

    for (int i = 0; i < count; i++)
    {
        float sin, cos;
        ModelHelper.GetSinAndCosCheap(randoms[i], out sin, out cos);
    }

    arrayTimes[c] = (int)ss.Elapsed.Ticks;
}

for (int i = 0; i < 100; i++)
    Console.WriteLine(mathTimes[i]);

Console.WriteLine("\n-----\n");

for (int i = 0; i < 100; i++)
    Console.WriteLine(arrayTimes[i]);