The power supply does have a daughter board. This board supports an 8 pin cable that splits off into 2x 6 pin connections.
Power supply extended card part number is M6NP2:
It goes here ( this is a picture with the power supply removed ):
6 PIN splitter cable part number D92C9:
Precision 5810 power supply part numbers:
YFY1V - 425W PSU
VDY4N - 685W PSU
RHHKV - 825W PSU