My Mobo has a 24 pin ATX plus a separate 4pin ATX12v. The 120W Pico PSU I have only has a 20pin ATX. I can add a Molex to 4pin ATX12v but what about the missing 4 pins in the main Connector? I need to power the i3, plus a Blue Ray and HD drives. No discrete graphics card on this system. Are those extra 4 pins required?
Woah, old topic but to answer your question, 20 pin is compatible with the 24 pin outlet(Carc369, your wrong here). SO yes it should totally work, just plug it in with the four pins not connected (like this)
With only the 20 pins connected, maximum draw is reduced to around 330w(well underneither the max your pico PSU can supply). With a low powered i3 you should be fine, only concern is the blu-ray drive during start-up(spin up) draw quite a bit of power, but definitely in range of the super ultra efficient Pico line.