Typically the 7950 has been regarded as a really great overclocker if you are willing to put them time into it. I still am very guarded about saying that a card is a good overclocker. I'm wiser then that. Basically I look at every chip and release that there are thermal limits I realize that not every chip is created equal and that when I push more power into my card that there is a change that the temperatures can be higher then another person with the same exact card. And because of this I believe that its a mix of a good card so for example the Vapor-X comes with components that are superior to a stock card (caps, mosfets, chokes) so it has an advantage there however, there is still the silicon chip which will have its limits as well.
So, basically the way I feel is this any card can be a great overclocker. AMD has more headroom because Nvidia has a bit more safeguards and things that the manufactures are unable to enable for the Nvidia cards to protect people from doing something dumb. AMD has always been the pusher for overclocking even there CPU's hold quite a few overclocking records where Intel doesn't even touch.
In terms of your temperatures. I wouldn't feel comfortable with those temperatures either But I would also look into your cases's cooling situation. I have a coolermaster sniper and it has amazing cooling i have a 200mm fan at the front of my case pushing air, I have a back exhaust, and my h100 has the fans pushing the air through the fins and through the ventilation at the top of the case. What is the point of telling you this I had 2x 560ti's at one point during the summer and they would hang around 75 degrees on load which is fine considering they were reference coolers. But I wanted a new case and picked up the 600T case from Corsair because its a nice case has nice Aesthetics and things that were not included within my case since my case was dated. Well the temperatures went up a lot I went from my current temps to around 85 almost 90 my cards were breathing crazy hot air out. I ended up returning the case. So I would evaluate your cooling situation to its a 2 way street with your card.
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