Hi,
For network performance, most likely not or less impact, as the checksum value is only significant for the receiving end, not the medium (network link) is uses to travel. In this case, the sender can always re-send the packet back.
Unless, of course, if the sender repeatedly/ continuously sent the same packet non-stop that probably makes the receiving host busy. This is noticable if online application is being used (session hang, slow, etc). If session like FTP, it will be a one-time session only, and need manual restart.
Rgds,
AK