You could try if you already own the psu.
No damage should occur if there is insufficient power.
The R9 cards are somewhat power hungry.
Here is a chart that gives you some idea of what you need. For cf R9-290 it says 1000w.http://www.realhardtechx.com/index_archivos/Page362.htm
The corsair CX series are merely OK, and I might be concerned about overstressing them.