Here is a diff to enable the checksum offload support for ix(4). Looking for any testing.
Index: if_ix.c =================================================================== RCS file: /home/cvs/src/sys/dev/pci/if_ix.c,v retrieving revision 1.92 diff -u -p -r1.92 if_ix.c --- if_ix.c 23 Aug 2013 19:44:14 -0000 1.92 +++ if_ix.c 9 Sep 2013 18:47:15 -0000 @@ -1543,9 +1543,7 @@ ixgbe_setup_interface(struct ix_softc *s ifp->if_capabilities |= IFCAP_VLAN_HWTAGGING; #endif -#ifdef IX_CSUM_OFFLOAD ifp->if_capabilities |= IFCAP_CSUM_TCPv4 | IFCAP_CSUM_UDPv4; -#endif /* * Specify the media types supported by this sc and register -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.