My previous (followup) reply crossed yours in the mail.
Quote: Originally Posted by Diogones
Thanks for your prompt and helpful reply profdlp! I really appreciate your help.
OK, so I should check my PSU cords to find out whether or not the 5V is connected to the 12V, or if it is connected to the PSU separately? If it is connected separately - it has its own set of wires - then it would only be providing 5V, instead of 12V if it were sharing a connection with the 12V hookup, right?
First, I would make sure that the smaller connector from the PSU uses all four wires. If there is a Y-Adapter anywhere inline make sure it uses all four wires, too. I've seen some fan connectors which only needed the 5V or the 12V and didn't have both.
There is a pinout diagram of what each wire does here: http://en.wikipedia.org/wiki/Molex
Turning to the Power Supply question, you'll notice that the wires coming out are in separate bundles. Some PSUs run everything off of one big rail, meaning the total power is shared among all the connectors as needed. Other (Multi-Rail) units split the total power into chunks. For example, there might be two 50W rails instead of one 100W rail. The reason I mention this is that it's possible that the PSU you have doesn't pump a lot of juice into the Molex connectors, since they're used mainly for lower power devices these days, and instead saves the heavy duty power for the special connectors for your graphics cards, etc.