Insert with Entity Framework very slow

Question

We have a piece of code that makes a bulk insert using the lib EntityFramework.BulkInsert-ef6-ext. We are facing some performance issues: The whole process of doing some work + inserting data takes about 150ms. That seems a lot as it was on my developer machine where only I'm working. I assume that on our production server this process is a lot slower as there is many traffic on it.

My first assumption was that the bulk insert is slower as single inserts when having only a few datarows.

I set up a small test app that traces the time during insert. Here are my results for 1 row:

Profiler:

1. bulk: cpu (31), reads(1809), duration(29)
2. single: cpu(0), reads(13), duration(1)

But looking at the traced time in my c# code shows a completly different picture:

bulk: 85ms

single: 130ms

Now two questions arise:

1. Why is there so much overhead when doing inserts with EF? How can this be reduced?
2. Is there a possibility to speedup single inserts with EF?

Finally here is my test code:

static void Main(string[] args)
{
    var sw = new Stopwatch();
    long t1, t2 = 0;

    using (var ctx = new TestContext())
    {
        var list = new List<Customer>();

        for (int i = 0; i < 1; i++)
        {
            list.Add(new Customer());
        }

        sw.Start();
        ctx.BulkInsert(list);
        ctx.SaveChanges();
    }

    sw.Stop();
    t1 = sw.ElapsedMilliseconds;

    sw.Reset();

    using (var ctx = new TestContext())
    {
        var trx = new TransactionScope();
        ctx.Configuration.LazyLoadingEnabled = false;
        ctx.Configuration.AutoDetectChangesEnabled = false;
        ctx.Configuration.ValidateOnSaveEnabled = false;
        var list = new List<Customer>();

        for (int i = 0; i < 1; i++)
        {
            ctx.Customer.Add(new Customer());
        }

        sw.Start();
        ctx.SaveChanges();
        trx.Complete();
        trx.Dispose();
    }

    sw.Stop();
    t2 = sw.ElapsedMilliseconds;
}

Best regards, Josef