This may apply to other brands of power supplies as well, but Antec no longer includes -5V lines on their power supplies. I have an EA-430, EA-500 and TruePower 430 and none of them offer -5V.
Anyway, I want to supply a couple of case fans with 7V instead of 5V or 12V since they are really noisy at 12V and run too slow at 5V. As I understand it, if I swap the -12V and -5V lines on the molex connector for the fan, it would provide the fan with 7V instead of 12V. The problem is, my power supply uses 5V, -12V, -12V, 12V on the molex connector. That means I get 12V no matter which ground I use. Since Antec doesn't provide a -5V, am I out of luck?
I do have the option of purchasing a fan controller or soldiering a resister in-line, but I was pretty disappointed when I discovered this since it would have been a easy/cheap mod.