You're not running a continuous stream of 64-byte packets in a home or SME setup. Also, assuming a 1:1 mapping to packet processing is a false dichotomy these days, NICs are doing an unbelievable amount of preprocessing, particularly grouping related packets together.
No, of course not. A good starting point for real world performance benchmarking could be e.g. IMIX [1].
The example above represents the solely theroretical worst case as a means to establish a baseline for performance benchmarking.
Anyway, if you are referring to HW offloading capabilities of "modern" NIC's, using techniques like LRO would break the "end-to-end"-principle of a router.
