One has a PHAT heat sink and the other doesn't. Therefore one gets a lot hotter then the other one and probably OC's better.
any one which mobo has phat heat sink is it DS3P or DS3R?
The second one supports 2 pci-ex the first will not and the first has memory issues, warns to buy memory from there selected list on there web site."
first of all, one of the pci-e on the second one isnt really full pci-e, its pci e 4x.
second, neither has memory issues. gigabyte has a list of TESTED AND PROVEN memory for some of its boards. YOU DONT HAVE TO USE THE LISTED MEMORY, other can work. its just that they know for a fact that those will work.