My current PSU (rated at 500W) only has a single 6pin connector for a GPU. I have the opportunity to swap my 8800GTS 320MB for a 9800GTX+ 512MB at no cost (the other party doesn't need the horsepower). From the PSU calculators I've used, the 500W should be enough.
However, the 9800 requires two 6pin power connectors to work. Since I don't have a second one attached to my PSU, does this mean I am out of luck and won't be able to power the card? Or can I add an additional 6 pin by connecting it to one of the unused white 12V connectors? I believe the 9800 has one included in the box.
Yes. The molex to 6 pin adapter has two molex connectors on one end and the 6 pin PCI-Express connector on the other end. Plug both molex connectors into the power supply. Video cards that require two 6 pin connections usually come with the adapter. If not, the adapter can be purchased for a few dollars from online vendors.
Huntkey is mainland China's largest power supply manufacturer. The power supplies they sell in Europe under their own company name lack PFC which is an EU requirement. They are also sold in the USA under the Dynex and Rocketfish brand names. Technical reviews indicate their power supplies perform very poorly and cannot deliver their advertised power ratings. Data labels on the psu's have false information. Some of them exploded during testing. Definitely not recommended.
Here are links to six technical reviews of different Huntkey power supplies: