power stops while CPU power connecting on motherboard

While connecting the CPU voltage (4 pin, 12v and GND) the SMPS is not switching on, if we connecting only motherboard power (20 Pin) and the CPU power in disconnected state the SMPS is switching on, Can anybody sortout my proble, find any remedy, if so Please help to resolve the same

What is your psu wattage

yea voltages tend to fluctuate always pay close attention to the 12v rails and cpu voltage

it’s defiently worth a look into.