Question : Problem: Replacing the power supply in a Vostro 420

The PSU I have is a 420W PC Power & Cooling 420W
http://www.pcpower.com/downloads/Diagram_3856.pdf

The PSU in the vostro is a 350W Liteon.
http://support.dell.com/support/edocs/systems/vos420/en/sm/psu.htm#wp1181010

The pin assignments look the same, but there is an extra wire running to the 11th pin slot in the PC&C PSU and it's running to the 24th pins lot of the Lite-On in the Dell.  Does it matter to which pin slot this extra wire is running?  Basically, I'm wondering if anybody knows if the PSU in the Vostro 420 is proprietary or not.

The Lite-On has decent specs for an OEM PSU, but has dual +12V rails where the PC&C has a single rail.  I'm trying to add a GTS 250 to it.

Answer : Problem: Replacing the power supply in a Vostro 420

No, the Vostro 420 PSU is not proprietary. Your PC Power & Cooling will work fine in it. I know several people that have replaced power supplies in the Vostro so they could stick a better video card in it.

If your still not sure, please clarify the colors of the extra wires. The 24th pin on the ATX 2 standard is just a ground while the 11th pin is the +12V.