Also bear in mind that many of today's network cards have processors in them that handle much of the TCP/IP overhead.
Intel's I210 controllers support offloading:
> Other performance-enhancing features include IPv4 and IPv6 checksum offload, TCP/UDP checksum offload, extended Tx descriptors for more offload capabilities, up to 256 KB TCP segmentation (TSO v2), header splitting, 40 KB packet buffer size, and 9.5 KB Jumbo Frame support.
* https://cdrdv2-public.intel.com/327935/327935-Intel%20Ethern...
And cost US$ 22:
Even those garbage tg3 things from 1999 that OEMs are still putting onboard of enterprise servers have some TCP offload capability.