I have bought a Gigabyte P75 D3 mainboard. It requires an ATX 2x4 connector to power the CPU. I have connected the two 4-pin connectors there and it seems to run fine with the i5 3570 processor.
Is it a right way to do that? My CM Extreme Power 650 PSU doesn't have a 4x2 pin connector.
The connector that you are referring to is actually an 8 pin EPS connector. EPS is a derivative of the ATX12v specification designed for higher power platforms. ATX12v specifies only a 4 pin auxiliary power connector in addition to the 24 pin main connector. EPS specifies a 24 pin main connector, 8 pin auxiliary connector, and an optional 4 pin tertiary connector (there's one on the Rampage IV Extreme). For compatibility purposes, the 8 pin female EPS connector is keyed such that a 4 pin male ATX connector can fit into it. Furthermore, most PSU manufacturers split the 8 pin male EPS connector into two 4 pin connectors such that it can fit into a 4 pin female ATX connector.