Using an accurate oscillator and analyzing both software and hardware system, sotware time-stamping on non-RT linux exceeds GPS based dedicated hardware accuracy. PCC (Processor Cycle Counter) is obtained nearest to network in packet Tx/Rx processing. System is tuned to reduce resource competition. A low jitter characteristics NIC (Network Interface Card) is chosen. Using these techniques, software time-stamp has jitter with standard deviation of 34 ns.