20 pin PSU into a 24 pin MOBO?

[Venzen007]

Just opened my DELL to put in a new PSU. Motherboard has a 24 pin connector with an additional little plug toward the back, which the new PSU seems to also supply. The problem is the new PSU only has a 20 pin mobo connector.

I've also just bought a dedicated graphics card, Radeon HD 7770. The computer was previously using integrated.

Can I use this power supply? Is there a particular way to connect it. Line up the top? Line up the bottom/ Stick it directly in the middle, leaving 2 pins open on both sides?

New PSU is a Seasonic S12II (Bronze), 520W ATX 12V.
Mobo is a PCI-E Gen.2 G43T-DMI V:A00

Thanks

 

[Venzen007]

Looks like potentially the PSU was a 24, but 4 of the pins were detached, but in same sleeve.

The little 4 pin on the opposite side of the mobo power set I just plugged with another 4 pin. 6 pin for the graphics card, and started it up.

Seems to be working.