A network device transfers packets from a packet memory to one or more network interfaces for transmission by the one or more network interfaces. The transferring of packets includes transferring the packets via one or more respective transmit data paths that correspond to one or more respective network interfaces. The network device measures one or more respective amounts of time required to transmit respective packet data within the one or more respective transmit data paths. The network device uses the one or more respective measured amounts of time to determine when to start transfer of packets from the packet memory to the one or more network interfaces via the one or more respective transmit data paths.