Sorry for the misunderstanding.
The test sets can inject any size packet desired (or a mix of packet sizes). When the test sets inject smaller packets, the difference between the 450 and the 450i becomes more apparent, because the 450i can process packets more quickly, so the throughput gain seen during this comparison is greater.
Neither the PMP 450 nor the PMP 450i control the packet size of the data that is flowing over the link.
Also, thanks for attending and that slide we were unable to present can be seen in the recording of the earlier webinar.