Tanmoy Saha said:
550w PSU is enough for gtx 650.
Choose corsair 550w PSU 80+gold or sesonic brand PSU. These two brands are best for PSUs.
how about corsair cx430 or vx 450 ?
The cx 430 has many bad reviews or vx has also same quality. Choose minimum 500w PSU from corsair or sesonic. Remember get 80+ certified PSU for best quality, stability, and also reliability.
A good PSU can give the whole system long and safe life .