TcpClient远程传输文件过慢的问题！

发送端的代码 bufferSize=20096;                Stream stream = new FileStream(fileName, FileMode.Open);
                int size = 0;//初始化读取流变量
                   long readLength = 0;//初始化已经读取的字节变量
                 
                 try
                    {
                        //从文件读字节、向流写字节
                        while (readLength < fileLength/*文件总大小/)
                        {
                            byte[] fileBuffer = new byte[bufferSize];
                            size = stream.Read(fileBuffer, 0, bufferSize);
                            nks.Write(fileBuffer, 0, size);
                            readLength += size;
                            showMessage(readLength, fileLength);
                        }
                        stream.Close();
                 接收端的代码 bufferSize=20096;
                            int size = 0;
                            int readL = 0;
                            byte[] fileByte = new byte[bufferSize];
                            stream = new FileStream(dirPath, FileMode.OpenOrCreate);
                            while ((size = nks.Read(fileByte, 0, bufferSize)) > 0)
                            {                                stream.Write(fileByte, 0, size);
                                readL += size;
                                showMessage(readL, fileLength);                            }
                            stream.Close();测试没有问题的，读写都正常，切很稳定，但是局域网传输一个400MB的影视文件要用600秒，是否可以进一步优化呢？