Why is the method, I think of to be the quicker one, the slower one?

I've currently got two methods for checking if a number is prime or not and another method to calculate the time both need.

IsPrime1:

bool IsPrime1(int i)
{
    if (i == 2 || i == 3 || i == 5 || i == 7) return true;
    return i % 2 != 0 && i % 3 != 0 && i % 5 != 0 && i % 7 != 0 && i % 9 != 0;
}

IsPrime2:

bool IsPrime2(int i)
{
    if (i == 2 || i == 3 || i == 5 || i == 7) return true;
    if (i % 2 == 0) return false;
    if (i % 3 == 0) return false;
    if (i % 5 == 0) return false;
    if (i % 7 == 0) return false;
    return i % 9 != 0;
}

CheckForTicks:

string CheckForTicks(int ticks)
{
    var sw1 = Stopwatch.StartNew();
    for (var g = 0; g < ticks; g++)
    {
        var b = IsPrime1(g);
    }
    sw1.Stop();

    var sw2 = Stopwatch.StartNew();
    for (var g = 0; g < ticks; g++)
    {
        var b = IsPrime2(g);
    }
    sw2.Stop();

    return $"{ticks} ticks: IsPrime1: {sw1.ElapsedMilliseconds} ms / IsPrime2: {sw2.ElapsedMilliseconds} ms";
    //equal to the following:
    //return string.Format("{0} ticks: IsPrim1e: {1} ms / IsPrime2: {2} ms", ticks, sw1.ElapsedMilliseconds, sw2.ElapsedMilliseconds);
}

Results:

| CheckForTicks | IsPrime1 (in ms) | IsPrime2 (in ms) |
|---------------|------------------|------------------|
|        100000 |                3 |                4 |
|        500000 |               18 |               21 |
|       1000000 |               37 |               45 |
|       5000000 |              221 |              242 |
|      10000000 |              402 |              499 |
|      50000000 |             2212 |             2320 |
|     100000000 |             4377 |             4676 |
|     500000000 |            22125 |            23786 |

What I wonder is, why IsPrime2 is even slightly slower than IsPrime1.
From my point of view IsPrime2 should be much quicker as IsPrime1 because it only has to check once before the first possible return and IsPrime1 checks all possibilities.
Is there something I don't know about or is this related to .NET?

I'd be very appreciated if somebody can explain the cause of this to me.

Thanks in advance!

PS: I'm using Visual Studio 2015 RC and .NET 4.6.