My 290 ran at 96C when mining at 820kH/s (the highest stable I could get, but then again my card seems to be a crappy one. Driver crashes alot when i stop mining and restart etc.)
Now it runs at 65C with watercooling and the same 820kH/s. If i increase intesnity the kH/s decreases. Sux...
I think there is a ton of variance in the power / heat attributes for R9 290 cards.
I have two sapphire 290's. Both hash very stable at 875Kh/s with the exact same settings, but the first runs at 73C at 60% fan while the second goes over 95C even with 75% fan, which forces me to run the fan at 90% and temps are still 88C. So
290 #1: 73C at 60% fan
290 #2: 88C at 90% fan
To make it an apples to apples comparison
290 #1: 62C at 90% fan
290 #2: 88C at 90% fan