Thats where silicon lottery kicks in as some of the cards are already maxed out at factory settings like aorus extreme while others are can be oc without problem.Also different algos different power draw and oc
Yah while I like how cool and quiet the aorus extreme runs I've noticed is about maxed out of the box. I can barely overclock it at all before it becomes unstable. My evga sc2 on the other hand while not clocked as high out of the box is able to run higher clocks after adjustment vs. the aorus.
Both are IMO good cards. Heat and clocks you can get are heavily dependent on algorithm. I typically don't like to run them over about 65c for long periods of time. Probably don't need to worry about it I just like to be on the safe side.