Excel benchmark read_write

public class PerformanceTests 
{
    [Test]
    public void ReadSpeedTest()
    {
        var excelApp = new Application();
        var workbook = excelApp.Workbooks.Add();
        var sheet = (Worksheet)workbook.Worksheets[1];
        var ns = new[] { 10, 100, 1000, 10000 };
        BatchWrite(sheet, ns.Max());
        var stopwatch = Stopwatch.StartNew();
        foreach (var n in ns)
        {
            stopwatch.Restart();
            object[] values1 = SeparateReads(sheet, n);
            Console.WriteLine("SeparateReads(sheet, " + n + "); took: " + stopwatch.ElapsedMilliseconds + " ms");
            Assert.AreEqual(n, values1.Length);
            Assert.AreEqual(0, values1.GetLowerBound(0));

            stopwatch.Restart();
            object[,] values2 = BatchRead(sheet, n);
            Console.WriteLine("BatchRead(sheet, " + n + "); took: " + stopwatch.ElapsedMilliseconds + " ms");
            Assert.AreEqual(n, values2.Length);
            Assert.AreEqual(1, values2.GetLowerBound(0));
            Assert.AreEqual(1, values2.GetLowerBound(1));
        }

        workbook.Close(false);
        Marshal.FinalReleaseComObject(excelApp);
    }

    [Test]
    public void WriteSpeedTest()
    {
        var excelApp = new Application();
        var workbook = excelApp.Workbooks.Add();
        var sheet = (Worksheet)workbook.Worksheets[1];
        var ns = new[] { 10, 100, 1000, 10000 };
        var stopwatch = Stopwatch.StartNew();
        foreach (var n in ns)
        {
            stopwatch.Restart();
            SeparateWrites(sheet, n);
            Console.WriteLine("SeparateWrites(sheet, " + n + "); took: " + stopwatch.ElapsedMilliseconds + " ms");

            stopwatch.Restart();
            BatchWrite(sheet, n);
            Console.WriteLine("BatchWrite(sheet, " + n + "); took: " + stopwatch.ElapsedMilliseconds + " ms");
        }

        workbook.SaveAs(Path.Combine(@"C:\TEMP", "Test"), ConflictResolution: XlSaveConflictResolution.xlLocalSessionChanges);
        workbook.Close(false);
        Marshal.FinalReleaseComObject(excelApp);
    }

    private static void BatchWrite(Worksheet sheet, int n)
    {
        string[,] values = new string[n, 1];
        var array = Enumerable.Range(1, n).ToArray();
        for (var index = 0; index < array.Length; index++)
        {
            values[index, 0] = array[index].ToString();
        }

        sheet.Range["B1", "B" + n].set_Value(null, values);
    }

    private static void SeparateWrites(Worksheet sheet, int n)
    {
        for (int i = 1; i <= n; i++)
        {
            sheet.Cells[i, 1].Value = i.ToString();
        }
    }

    private static object[,] BatchRead(Worksheet sheet, int n)
    {
        var range = sheet.get_Range("A1", "A" + n);
        var reads = (object[,])range.Value2;
        return reads;
    }

    private static object[] SeparateReads(Worksheet sheet, int n)
    {
        var reads = new object[n];
        for (int i = 1; i <= n; i++)
        {
            reads[i - 1] = sheet.Cells[i, 1].Value2;
        }
        return reads;
    }

    private T TimeAndInvoke<T>(Func<T> func, string message)
    {
        var stopwatch = Stopwatch.StartNew();
        stopwatch.Restart();
        T retval = func();
        Console.WriteLine(message + " took " + stopwatch.GetTimeString());
        return retval;
    }
}

gistfile1.txt

Results read:
SeparateReads(sheet, 10); took: 77 ms
BatchRead(sheet, 10); took: 83 ms
SeparateReads(sheet, 100); took: 75 ms
BatchRead(sheet, 100); took: 0 ms
SeparateReads(sheet, 1000); took: 766 ms
BatchRead(sheet, 1000); took: 0 ms
SeparateReads(sheet, 10000); took: 8428 ms
BatchRead(sheet, 10000); took: 2 ms

Results write:
SeparateWrites(sheet, 10); took: 23 ms
BatchWrite(sheet, 10); took: 0 ms
SeparateWrites(sheet, 100); took: 96 ms
BatchWrite(sheet, 100); took: 1 ms
SeparateWrites(sheet, 1000); took: 944 ms
BatchWrite(sheet, 1000); took: 2 ms
SeparateWrites(sheet, 10000); took: 10669 ms
BatchWrite(sheet, 10000); took: 13 ms