Eu tenho um arquivo grande de tamanho de memória 42 mb. Quero baixar o arquivo com menos consumo de memória.
Código do Controlador

public ActionResult Download()
{
    var filePath = "file path in server";
    FileInfo file = new FileInfo(filePath);
    Response.ContentType = "application/zip";                        
    Response.AppendHeader("Content-Disposition", "attachment; filename=folder.zip");                   
    Response.TransmitFile(file.FullName);
    Response.End(); 
}

método alternativo tentado comCorrente

public ActionResult Download()
{           
    string failure = string.Empty;
    Stream stream = null;
    int bytesToRead = 10000;


    long LengthToRead;
    try
    {
        var path = "file path from server";
        FileWebRequest fileRequest = (FileWebRequest)FileWebRequest.Create(path);
        FileWebResponse fileResponse = (FileWebResponse)fileRequest.GetResponse();

        if (fileRequest.ContentLength > 0)
            fileResponse.ContentLength = fileRequest.ContentLength;

        //Get the Stream returned from the response
        stream = fileResponse.GetResponseStream();

        LengthToRead = stream.Length;

        //Indicate the type of data being sent
        Response.ContentType = "application/octet-stream";

        //Name the file 
        Response.AddHeader("Content-Disposition", "attachment; filename=SolutionWizardDesktopClient.zip");
        Response.AddHeader("Content-Length", fileResponse.ContentLength.ToString());

        int length;
        do
        {
            // Verify that the client is connected.
            if (Response.IsClientConnected)
            {
                byte[] buffer = new Byte[bytesToRead];

                // Read data into the buffer.
                length = stream.Read(buffer, 0, bytesToRead);

                // and write it out to the response's output stream
                Response.OutputStream.Write(buffer, 0, length);

                // Flush the data
                Response.Flush();

                //Clear the buffer
                LengthToRead = LengthToRead - length;
            }
            else
            {
                // cancel the download if client has disconnected
                LengthToRead = -1;
            }
        } while (LengthToRead > 0); //Repeat until no data is read

    }
    finally
    {
        if (stream != null)
        {
            //Close the input stream                   
            stream.Close();
        }
        Response.End();
        Response.Close();
    }
    return View("Failed");
}

devido ao tamanho do arquivo, ele está consumindo mais memória, o que leva a um problema de desempenho.
Após fazer o check-in do iis log, o processo de download leva 42 e 64 mb, respectivamente.
desde já, obrigado