Personally I would call anything over 80 degrees C too hot, but 90 isn't in the danger zone just yet.
I should have specified what I meant by danger zone. Don't expect a crippling failure at 90 degrees in the short run, but it's going to shorten it's life expectancy in the long run.
are they getting so hot because they are in this huge gaming case that the store installed everything into? I see on youtube videos that most people just have the cards out in the open on a table. or is it for some other reason? Should I take everything out of the casing? I started up the other 3 cards and they started immediately going to 100 celsius so I have everything shut down for now.