Dell XPS/Dimension XPS Gen 4 - Manual (Page 53)

DC Power Connectors BAY 1 and BAY 2
1 +3.3 VDC Orange
2 COM Black
3 +5 VDC Red
4 COM Black
5 +12 VB DC White
Pin Number Signal Name 18-AWG Wire Color
1 +12 VB DC White
2 COM Black
3 COM Black
4 +5V DC Red