eimazuba :
I have a normal 24 pin PSU output (5 cm x 0.8 cm),
but my motherboard has 2x time smaller 24 pin input (3.5cm x 0.5cm).
What adapter do I need, and how are these connections called?
Motherboard is from Dell OptiPlex 760 SFF
Unfortunately, you are dealing with a proprietary machine that uses a non-standard ATX power supply connector that is smaller to fit in the very small size case. What I am told is that the unit does use a regular ATX connector, but it is a small version, meaning the wiring is the same as the ATX, but the plug is non-standard or reduced in size.
Therefore, regardless of what ATX power supply you use, it won't fit the motherboard plug, unless you get the slimline power supply. I am not aware of an adapter that will work in this instance.
The OEM Dell power supply that supports this board goes for about $50.