C++ program compiled for x64 is slower than compiled for x86

#include <xmmintrin.h>

#include "timer.h"

#include <vector>
#include <iostream>
#include <algorithm>

/********************DECLARATIONS************************************************/
class Vector
{
public:
    Vector():x(0),y(0),z(0){}

    Vector(double x, double y, double z)
        : x(x)
        , y(y)
        , z(z)
    {
    }

    double x;
    double y;
    double z;
};

double Dot(const Vector& a, const Vector& b)
{
    return a.x * b.x + a.y * b.y + a.z * b.z;
}

class Vector2
{
public:
    typedef double value_type;

    Vector2():x(0),y(0){}

    Vector2(double x, double y)
        : x(x)
        , y(y)
    {
    }

    double x;
    double y;
};

/******************************TESTS***************************************************/

void Test(const std::vector<Vector>& m, std::vector<Vector2>& m2)
{
    Vector axisX(0.3f, 0.001f, 0.25f);
    Vector axisY(0.043f, 0.021f, 0.45f);

    std::vector<Vector2>::iterator i2 = m2.begin();

    std::for_each(m.begin(), m.end(),
        [&](const Vector& v)
    {
        Vector2 r(0,0);
        r.x = Dot(axisX, v);
        r.y = Dot(axisY, v);

        (*i2) = r;
        ++i2;
    });
}

void TestSIMD(const std::vector<Vector>& m, std::vector<Vector2>& m2)
{
    Vector axisX(0.3f, 0.001f, 0.25f);
    Vector axisY(0.043f, 0.021f, 0.45f);

    __m128d ax = _mm_set_pd(axisX.x, axisY.x);
    __m128d ay = _mm_set_pd(axisX.y, axisY.y);
    __m128d az = _mm_set_pd(axisX.z, axisY.z);

    std::vector<Vector2>::iterator i2 = m2.begin();

    std::for_each(m.begin(), m.end(),
        [&](const Vector& v)
    {
        __m128d x = _mm_set_pd(v.x, v.x);
        __m128d y = _mm_set_pd(v.y, v.y);
        __m128d z = _mm_set_pd(v.z, v.z);

        __m128d xx = _mm_mul_pd(x, ax);
        __m128d yy = _mm_mul_pd(y, ay);
        __m128d zz = _mm_mul_pd(z, az);

        __m128d xy = _mm_add_pd(xx, yy);
        __m128d xyz = _mm_add_pd(xy, zz);

        _mm_storeh_pd(&(*i2).x, xyz);
        _mm_storel_pd(&(*i2).y, xyz);
        ++i2;
    });
}

int main()
{
    cpptask::Timer timer;

    int len2 = 300;
    size_t len = 5000000;
    std::vector<Vector> m;
    m.reserve(len);
    for (size_t i = 0; i < len; ++i)
    {
        m.push_back(Vector(i * 0.2345, i * 2.67, i * 0.98));
    }

    /***********************************************************************************/
    {
        std::vector<Vector2> m2(m.size());
        double time = 0;
        for (int i = 0; i < len2; ++i)
        {
            timer.Start();
            Test(m, m2);
            time += timer.End();
        }
        std::cout << "Dot product double - " << time / len2 << std::endl;
    }
    /***********************************************************************************/
    {
        std::vector<Vector2> m2(m.size());
        double time = 0;
        for (int i = 0; i < len2; ++i)
        {
            timer.Start();
            TestSIMD(m, m2);
            time += timer.End();
        }
        std::cout << "Dot product SIMD double - " <<  time / len2 << std::endl;
    }
    /***********************************************************************************/

    return 0;
}