i am going to extend the 4 pin connector from the power supply that connects to the mother board near the cpu. i have an antec 500w smartpower 2.0 and the 4 wires going to this connector are 2 black and 2 yellow with black stripes. my question is, are the two black the same to each other and are the 2 yellow with black strips the same to each other as in same power and such?

There should be two +12vs (yellow) and two 12v grounds on the P4 connector, which you should be able to mix. However, that PSU has dual rails, meaning that certain connectors are divided up. The manual does not specify which is on what rail, and it generally is not a good idea to mix the rails together(eg, take +12v from Rail #1 and use the ground from Rail #2) So you can't be sure unless you open up the PSU and check that both 12v lines are hooked to one separate rail. (Which I wouldn't recommend if you don't know what your doing and don't want to lose your warranty) I'm not responsible for any damage.

Rule of thumb, yellow=12v, Red=5v, orange=3.3v, black=ground However, on connectors like molex with different voltages, they are not the same, the grounds there correspond to wire next to it (EG: Yellow and the black next to it are 12v, the red and the black next to it are 5v) don't mix them.

So, I'd just make sure that you don't mix up the lines

thanks for the reply. i believe i understand it.

what are good ratings for the power ratings when a computer runs. my computer came with some monitoring software and the voltages do fluctuate very slightly. is there and amount of fluctuation that is acceptable?

There are indeed acceptable variations. Check out the ATX specifications (PDF), specifically section 4.1.4, entitled "Voltage Tolerances".

Manufacturers of good power supplies generally impose much stricter standards for voltage tolerances than the ATX standards call for. It's the cheap ones that you really need to watch out for.