82599EB vs 82599ES (10 Gigabit Ethernet Controller)

i looked at the product spec and both 82599EB and 82599ES features look the same to me.

the 82599ES is in the converged network adapter X520 product family.

is there any difference other than ES is newer generation so therefore might be more efficient? (just a guess because i haven’t seen any benchmark numbers.)

the reason i asked is because i am plan ahead if we are ok w/ 82599EB or should i just jump ahead to 82599ES because one of the vendor said the cabling requirement is different for the ES.  i think our cable vendor is blowing smoke but i just want to make sure.

here's the product spec:

http://ark.intel.com/products/32207/Intel-82599EB-10-Gigabit-Ethernet-Controller

Intel® Ethernet Converged Network Adapter X520 Product Family