On a server with 4 2GHz processors and Windows Server 2003 I have serial data coming in the COM1 port that is good most of the time. Once in awhile, the application expecting the data receives data that has been truncated and times out because the trailing ETX is missing. I have captured the data between the external device and the DB9 COM1 port using a protocol analyzer and it shows 30 to 40 byte packets going into the COM port. I have run PortMon (from Sysinternals) and found that the larger packets are read normally in 8 byte pieces. When things fall apart, the last thing PortMon shows is a 16 byte piece, and any remaining bytes that should have been after the 16th byte (based on what the protocol analyzer shows went into the port, there should be another 4 or 5 bytes) is lost. I did not have this problem with the same application and external device running under Windows Server 2000 on a slower machine (2 800Mhz processors). Any ideas where I should look next? The application uses Java and SQL 2000.