What’s needed is a 12V supply, at least 1.5A. You can get that from SATA as long as the power supply it’s attached back to has enough amperage available http://superuser.com/questions/752769/is-there-any-limit-on-how-many-sata-power-connectors-i-can-ext… Thanks for asking!
Hi Bruce,
Thanks for your question (and happy Thanksgiving!).
Yes, it’s recommended to connect the standard molex power connector (to an available connector from your PC’s power supply).
The reason why is the card gets all the power it needs for its own operation from the PCI Express bus, which has 12V and 3.3V lines. But PCI Express doesn’t have a 5V supply, which is what bus-powered USB devices need. The standard 4-pin molex has 12V and 5V lines. http://en.wikipedia.org/wiki/Molex
So without the molex connected, the card will actually work fine with self-powered USB 2.0 and 3.0 devices attached (those with their own AC adapter, like our http://www.amazon.com/Plugable-SuperS…) or if you have a self-powered USB 3.0 hub (like http://www.amazon.com/Good-Way-HU3140…) and connect all devices through that. But if you connect bus-powered devices directly to the card, they won’t get power.
To get all devices working, you’ll need the white 4-pin molex on the card connected to your power supply.
Hope that background helps. Thanks for your question!
Bernie