This non-standard ATX wiring is used on Dell systems dating from after September 1998 to the present.
20 pin MOLEX 39-29-9202 connector at the motherboard ?
18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300W configurations 16 AWG is recommended
20 pin MOLEX 39-01-2200 connector at the cable?