What miner are you using and what's your config like?
CGMiner 3.7.2 on windows 7.
I've been mostly trying with a default intensity 13,gputhreads 2 and some other default stuff.
(New to cgminer so don't know the names by heart)
R9 290 works with -g 1, which also means -i 18+ and TC higher than 20k
Try these:
-g 1 -i 19 --thread-concurrency 20481
I tried something similar at one point with my first gpu and even with a lower threadconcurrency but the degrees would almost hit 100.
The second one doesn't go higher than 65 degrees, 50% fan and 370kh/s. Have no idea why.