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