I have a little money to burn...

[geofelt]

A 260 can run with only one 6 pin connector? I hadn't tried. So why are there spots for two connections?

OOPS!!! my mistake, and I should know, my card is a gtx260, and I use two connectors..

 

[aevm]

Yeah, I think you have to. Apparently that card can consume 182W under load. With a single 6-pin connector I believe the most it could get is 75W from the slot and 75W from the connector.

@OP: if you don't have 4 6-pin PCI-E connectors you can buy some adapters. Some video cards include that kind of adapter in the box. Here's an example:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812887001&Tpk=adapter molex pci-e

 

[PsyKhiqZero]

Put a down payment on this
http://www.usa.denon.com/ProductDetails/3429.asp

It will make your internet faster,
Dedicated in and out will insure proper installation and reduced latency.
It will add 3 inches where ever you want it.

 

[j_chatelain]

Excellent question. I tried to figure out the answer but couldn't.

I found something else though, which is good news for you IMO:
http://www.guru3d.com/article/geforce-gtx-260-review/4

Recommended Power Supply

So here's my power supply recommendation:

GeForce GTX 260 | 280

* A GeForce GTX 260 requires you to have a 500 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 38 Amps available on the 12 volts rails.
* A GeForce GTX 280 requires you to have a 550 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 40 Amps available on the 12 volts rails.

GeForce GTX 260 | 280 SLI

* A second GeForce GTX 260 requires you to have a 700 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 50 Amps available on the 12 volts rails.
* A second GeForce GTX 280 requires you to have a 800 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 55 Amps available on the 12 volts rails.
* 3-way SLI ... well check our article on Wednesday please.

There are many good PSU's out there, please do have a look at our many PSU reviews as we have loads of recommended PSU's for you to check out in there. What would happen if your PSU can't cope with the load?:

* bad 3D performance
* crashing games
* spontaneous reset or imminent shutdown of the PC
* freezes during gameplay
* PSU overload can cause it to break down

Your PSU with 56A is above their recommended 50A.

Thanks, that's quite insightful.