So can I assume that it will have a dedicated AV chip in? Otherwise why would it be less of a burden on the system. There will still be new definitions to scan.

nvidia's integrated firewalls on motherboards didn't exactly go down well; everyone I know ends up switching them off.

AV is much harder to do in hardware. A firewall works at the perimeter on the network connection, while AV usually has to hook into IO operations of the OS and applications.

A perimeter AV solution would offer incomplete protection, in addition to causing similar problems to the integrated firewall. Such security devices do exist and have their uses, but there would be complications in producing a chipset solution. Regular updates for one; how to get them and where to store them.

It'll be interesting to see exactly what they produce, but I'm not speculating. I just hope it's not going to be some really bad software bundled free with Intel motherboards...