atx 24 pin to 20 pin confusion

[jdex24]

im trying to connect a 24 pin cable (power supply) to my 20 pin socket (on motherboard) ive read somewhere that it is possible to overhang the 4 extra pins but when i go to do this my motherboard has cathodes in the way. ive been really confused about the whole 20 pin to 24 pin adapters and im not sure if it will work this way around. also i read that it may be possible to stanly knife the extra 4 pins (not the wires) so that it would fit in place. the last thing is what do these extra 4 pins do. and to make things more confusing for me ive got another 4 pin slot on my motherboard and im not sure what goes into that. can someone please clearly explain because my head is about to explode.
cherz

 

[donkey42]

im trying to connect a 24 pin cable (power supply) to my 20 pin socket (on motherboard)

ideally you'd be best to get both ATX 2.2 mobo and PSU, rather than an ATX 2.0 mobo and an ATX 2.2 PSU, however there is a converter, but its not really concidered as being a long term solution, here is an adaptor / converter

 

[Big B]

Before attempting to mod the PSU, check to see if the last 4 pins detatch. Many 24-pin PSU's are designed as such for backward compatibility with 20-pin motherboards.