Yes 650watts, from Corsair (XFX, Antec, Seasonic) will power any SINGLE GPU..... with ease.
System: 200watts
GPU 250watts
Total: 450watts...........
I'm running CrossFire R9 280X's, with a Corsair HX850. System draws ONLY 600--650watts gaming.... so you will be fine
NOTE: AMD recommends 750watts Single AND 1000watts for a CrossFire pair, I believe they are trying to account for all the JUNK power supplies that "over rate" their power output with that 1000watt number....