PPS maxed out at ~20,000

[sterling-TAS]

Not sure if I am understanding everything correctly but I seem to be maxed out at around 20,000 PPS. I have generated the meta.json file and analyzed the PCAP that I am using in Wireshark. Based on what Wireshark says, the PPS of the file is 31,273. When running with TCPReplay, which I assume is not concurrent, it gets around 358.49 Mbps, 30042.16 pps. I understand that this is fast but just curious if I am missing something with this tool because it seems slower than TCPREPLAY. There are also no warning messages about not being able to maintain the original timing.