C# inefficient streaming to the hard disk

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C#

UDP

binary

streaming

I am currently working on a program that receives UDP packets of size 1460 bytes per packet and continuously streams the bytes to the hard drive of my PC. Currently, my program can only receive and stream 84 packets before data loss occurs. I need my program to be realtime with a fast sampling rate of 20 kHz. I need to be able to receive much more packets of data without loss.

My code connects to the client and waits for data to come in. When data comes in, the program receives the data, streams to the hard drive, then waits for more data. I think that I am not streaming fast enough, so I fail to receive the next packet of data that gets sent in.

Here is some code:

if (firsttimeflag == false) // Streaming each value to the hard disk 
   {
    using (BinaryWriter b = new BinaryWriter(File.Open(@"F:\file.bin", FileMode.Create)))
       {
           //Use foreach and write all values.
           foreach (int i in datain)
           {
             b.Write(i); // Writes a four byte signed integer.
           }
       }
             firsttimeflag = true;
     }
 else
     {
      using (BinaryWriter b = new BinaryWriter(File.Open(@"F:\file.bin", FileMode.Append)))
          {
            foreach (int i in datain)
              {
                b.Write(i);
              }
          }
      }

Where "datain" is the 1460 byte array which is converted to a string beforehand.

Any help would be appreciated. Where is the inefficiency of my code?

Thanks,
GabeA