Yes, it is true because WinPCAP works as a NDIS driver. It means that WinPCAP gets network packets faster. It happened because NDIS provides Layer 2 packets( for example Ethernet) but WFP works on Layer 4(transport layer, TCP/IP) and gets network packets later after some processing.
A simple flow of network data is
network->miniport NDIS driver → NDIS intermedia or protocol driver(WinPCAP works here)->Windows network kernel part->Any WFP installed drivers
Thanks. The source code analysis for this blog suggested that the sample driver being used for benchmarking had only one consumer thread to process the blocked packets. So the sample blocks all incoming packets and puts in a queue. A single thread takes it out from the queue one by one. This is the reason why it is slow.