Gigabtye has few superoverclocked graphic cards and I have no idea what those meant @@, I only know that overclocked graphic cards have slightly higher GPU clock speed but what's the difference between superoverclocked and overclocked?
The super overclock is a higher factory overclock then a regular card. You can buy a non overclocked card and overclock it yourself saving a few bucks. Use a program like EVGA Precision X or MSI Afterburner.
"SOC" "Super Overclocked" just a marketing term. More or less what others as said it's what Gigabyte uses to designate their slightly higher overclocked cards which may be higher binned.
Best bet is to just buy a card you want with a good heatsink on it (it's cheaper to buy one already installed by far) and OC yourself it's quite simple in comparison to overclocking everything else. If your lazy about it find the highest overclocked retail card and use the same settings they have and stress test it, I can almost guarantee you the card will work with those settings as the companies don't push them too far as they have to sell them in quantities.