In terms of wire speed, the packet is forwarded without delay and loss for any input of all ports of the router. RFC suggests the throughput of the router is checked with the short packet of 64-bit.e.g. one router has two 10M synchronic interface-one is for upstream and another is for downstream. The throughput is 10M/8/64=19531pps. As long as it handles 19531 64-bit packets every second, it can reach the handling of wire speed. Wire speed specified by RFC is lower. For the case above, if it reaches 14000pps, it can be called wire speed.
Generally the throughput can be improved with the following ways: reconstruct routing table, use Cache, distribution handling, high layer switching and hardware (FPGA/ASIC) forwarding.