I doubt your stressing the two 1GB connections,  so I will say no.    But, there certainly is some advantage if you are maxing out the current two 1GB connections.    The real question is?   Can the MD3220i controllers / chosen drive configs really handle 4 slammed 1GB connections?   
Hi, Currently we have a MD3000i with 2 controllers connecting via two switches to the VMware servers. Each VMware server has two iSCSI NIC's. We are looking at getting a MD3220i which has 4 controllers and 8 ports. Would there be any performance gain from putting more iSCSI NIC's into our new servers ? thanks, John
MD3220i - how many iSCSI NIC's on VMware servers ?