Why is QMap (and also std::map) significantly slower than MS .Net Dictionary class?

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I have the following C++ program:

#include <map>
#include <string>
#include <QDebug>
#include <QMap>
#include <QElapsedTimer>
 
using namespace std;
 
int main()
{
    QElapsedTimer t;
 
    qint64 e;
    const int COUNT = 1000000;
 
    // using std::map
    t.start();
    map<int,string> m;
    for(int i = 0; i < COUNT; i++)
        m[i] = "HI";
 
    e = t.elapsed();
    qDebug() << e;
 
    // using Map
    t.restart();
    QMap<int,string> m2;
    for(int i = 0; i < COUNT; i++)
        m2[i] = "HI";
    e = t.elapsed();
    qDebug() << e;
 
    return 0;
}

#include <map>
#include <string>
#include <QDebug>
#include <QMap>
#include <QElapsedTimer>

using namespace std;

int main()
{
    QElapsedTimer t;

    qint64 e;
    const int COUNT = 1000000;

    // using std::map
    t.start();
    map<int,string> m;
    for(int i = 0; i < COUNT; i++)
        m[i] = "HI";

    e = t.elapsed();
    qDebug() << e;

    // using Map
    t.restart();
    QMap<int,string> m2;
    for(int i = 0; i < COUNT; i++)
        m2[i] = "HI";
    e = t.elapsed();
    qDebug() << e;

    return 0;
}

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Compiled in release mode, the std::map version gives me a result of 208 ms, while the QMap version gives me a result of 220 ms.
But the .Net version is much faster

using System;
using System.Collections.Generic;
using System.Diagnostics;
internal class Program
{
    private static void Main()
    {
        Stopwatch w = Stopwatch.StartNew();
        Dictionary<int, string> dic = new Dictionary<int, string>();
        long e;
        const int COUNT = 1000000;
 
        for (int i = 0; i < COUNT; i++)
        {
            dic[i] = "HI";
        }
        w.Stop();
        e = w.ElapsedMilliseconds;
        Console.WriteLine(e);
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
internal class Program
{
    private static void Main()
    {
        Stopwatch w = Stopwatch.StartNew();
        Dictionary<int, string> dic = new Dictionary<int, string>();
        long e;
        const int COUNT = 1000000;

        for (int i = 0; i < COUNT; i++)
        {
            dic[i] = "HI";
        }
        w.Stop();
        e = w.ElapsedMilliseconds;
        Console.WriteLine(e);
    }
}

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This gives me a result of 60 ms!
Am I doing something wrong? Or the result is actually normal?