600 watts enough for r9 290x

Solution
Yes, I'm running a Tri-X R9 290 OC off the same PSU with no problems, but if your system has a heavily overclocked AMD CPU or other power hungry parts you might want to move to a 700 Watt unit.
A lot here will tell you the CX series are not good and they're not the best but they are serviceable, their main drawback is they use lower quality parts ( capacitors) that have a shorter life then those found in more expensive units.
Unless you're going to run the system 24/7 as a bitcoin miner I wouldn't worry.
Yes, I'm running a Tri-X R9 290 OC off the same PSU with no problems, but if your system has a heavily overclocked AMD CPU or other power hungry parts you might want to move to a 700 Watt unit.
A lot here will tell you the CX series are not good and they're not the best but they are serviceable, their main drawback is they use lower quality parts ( capacitors) that have a shorter life then those found in more expensive units.
Unless you're going to run the system 24/7 as a bitcoin miner I wouldn't worry.
 
Solution
Run the numbers here: http://extreme.outervision.com/psucalculatorlite.jsp
I ran a quick check that shows a recommended Wattage 550 with a heavily overclocked CPU ( 4.5GHz with 1.4V) but stock graphics card or 500 Watts recommended with a stock setup, your numbers will be a little different, I ramped up the fans, HDDs etc.
Bear in mind, these are heavily loaded results, you'll only get close to this level of draw with something like OCCT or Furmark.