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 .
i was going through the bench & other forums too,found that the 650 is bit pricey[Rs 1k] & overall 4% - 5 % ahead of 7750.
I'm thinking, is that 1k more is justified,if we look at the upcoming games at my resolution[1333x786] ?