This motherboard uses an Intel Power Connect or similar CPU power connector. (For the Dell Optiplex 790 LGA 1155 model)
This motherboard uses an Intel Power Connect or similar CPU power connector. (For the Dell Optiplex 790 LGA 1155 model)
The CPU connector on the left appears to be a 4-pin type, which may differ from the standard 24-pin used for modern CPUs. The motherboard model you mentioned supports DDR3 and uses an LGA1155 socket.
The motherboard seems to connect a standard CPU ATX-12V 4-pin power connector to provide electricity to the processor. The power cables from supply units can be divided between the CPU ATX 12V 4-pin or the CPU EPS, where they merge the two 2x2 cables into a 2x4 block.