What is this 4 pin slot connector on my motherboard?

[Loyde Kessroy]

I use a MSI Z68MA‑ED55 microATX Motherboard and I got a new corsair RM550X PSU for it.
When I unplugged the old one, it was connected to a 4 pin slot labeled JPWR2 and my new PSU doesn't have a cord for it. What is it and is this a necessary component? Thanks!

 

[Loyde Kessroy]

I found an odd looking 8 pin connector that seems like it might be able to split in two, but I want to make sure that's a good idea before I break it.

After trying I realized I could just stick the hole 8 pin connector thing on and overlap it, but is this safe?

 

[InvalidError]

I'm guessing you mean the square ATX12V cable. That's where the CPU's VRM gets its power from and the PC won't boot without it.

Most modern PSUs don't have a 4-pin ATX12V. Instead, they have a break-away EPS12 connector which is simply an ATX12V connector with an optional extra four pins on the side. Plug in the part that fits and make sure the unused half isn't shorting against anything if your motherboard doesn't have an 8-pin connector.