More aboutpower supply run cards 7770 vapor gtx 650
Not a reliable PSU at all. There is enough wattage but you want to swap it.
Corsair Seasonic XFX Antec Thermaltake
pick one from one of these manufacturers.
It will be more than enough. I would just choose another brand like Seasonic, Corsair, Antec, OCZ, Rosewill etc... the power usage of those cards are around 100 watts under load. the data sheets will also advise you to use 400-500W psu too.
I am a 7770 owner myself and I used to have an XFX 550W PSU which worked great! A reason why I went with the 7770 is for the low power consumption. I think you will be just fine. The 650 will work fine as well.
Thanks for you all
but i would like to know if i can push more to hd 7790 or gtx 650 ti boost. will it be ok for that or shall i stop at hd 7770 or gtx 650 ti ????
on a 550W power supply, you can use any of those cards. dont be worried. 650ti boost is a premium choice for its price. if you can afford ~150$ dont hesitate.