Old but good power supply, only one PCI-E power cable... need two

For a system using a single reference clocked Radeon HD 7870 GHz Edition graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 27 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.

Overclocking of the CPU and/or GPU(s) will require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock you are trying to achieve.

You may find power supplies on the market that supply more than enough Wattage to run the system. However, some of them lack Sufficient Amperage capacity on the critical +12 Volt rail, which is necessary to properly power the critical components in the system (i.e. CPU and GPUs). This is the reason why graphics card manufacturers may overstate the power supply wattage, usually by at least 50 Watts, in an attempt to take into account some of those power supplies that have the weaker +12 Volt rail(s).

The Antec EarthWatts Series 430 Watt (EA-430), with its maximum combined +12 Volt continuous current rating of 30 Amps and with one 6-pin PCI Express supplementary power connector, is electrically sufficient to power your system configuration with a single Radeon HD 7870 GHz Edition graphics card.

Some of the graphics card manufacturers will include one or two of these types of cables with their graphics card:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...