the heatpipe is only used to move heat from the sb to the nb and from the nb to the mosfet heatsink

the southbridge doesnt produce that much heat, so it doesnt need the heatpipe to remove the heat i guess.
the nb will be cooled well enough so it doesnt need the heatpipe to the pmw mosfets.
and the pmw mosfets have their own heatsink and dont need the heatpipe