Droop is the desired voltage-positioning slope in mV/A which means the output voltage has a load line where the output voltage will reduce by this rate for every 1A rise in load current. The selection of droop-in guided by Intel for its different versions of platforms as specified on the page 19 of the datasheet. For VR12/IMVP-7 ATOM CPU the droop should be 5.9m ohm and for VR12/IMVP-7 SV CPU/VR12/IMVP-7 XE CPU the droop should be 1.9m ohm.