No, CX-430 is not good choice. Go for CX-400 if its available.
Other choices are:
* TAGAN StoneRock 500W -- 3k
* FSP SAGAII 500W -- 2.1k
If you are really tight on budget, then go with FSP SAGAII 500W. It can handle 6670 easily as it has the same power consumption as that of 5670. And when a SAGAII 400W can handle 5670 with ease then why cant SAGAII 500W handle it.
IMO go for SAGAII 500W at 2.1k.