As the requirement of this card is as follows as it requires two 6 pin PCI-E power connector and i want to know it is it possible to use only one PCI-e 6 pin power connector as my smps has only one 6 pin power connector and the smps is 640W (Will it power the graphic card without much load) and i am also think of using molex to pci-e 6 pin power connector.
It requires two 6 pin power connectors, so no you can not use only one, I mean, that is kind of obvious.
However, you can use a molex to PCI-E 6 pin adapter for the 2nd power connector, that should not be an issue, provided your power supply is a quality unit. At 640W it has more than enough power, your card is rated to draw a maximum of 225W, although it is unlikely it will ever draw that much.
It might not draw as much as they stated but remember your other hardware comes into play as well they need power from the PS as well. So your PS has to be of high quality and efficiency to handle the load request by various hardware when running and idling. I have the similiar GPU as your but Black Edition and Antec 750W PS only cause I do have alot of hardware and HDD running in my system. You should check what kinda PS you have and what it can handle under load and its’ specs. No you will need an adapter that will give you another 6 pin otherwise your card won’t power up or work and will beep at you or refuse to come on. I haven’t tested by removing one 6pin connector as I don’t want to void my lifetime warranty on my GPU. I usually go by the manufacture specs on wattage rating but you have to take into account all your hardware as they draw power from the PS as well and how old your PS currently is. If you start to play GPU intensive game you might want to make sure your PS can handle the draw espically if you use higher resolution but if you don’t do that you should be fine just everyday computing and low res game or non intensive GPU games will run without any problem on the GPU.
Specification of my PSU as follows
Zebronics ZEB-640W Diamond
[+3.3V]+[+5V]: 250W Max
[+12V1]+[+12V2]: 300W Max
Its not a great brand, I hear the OEM might be eagletech. But it should power your card with both pci power connectors used.
The rail breakdown is not very impressive either, your PSU is an older ATX design. It will power your video card, but do not think about using that power supply for a multi-GPU system.
I am not going with sli . thinking of using only one card