Please help with Crossfire

So I just got my second 4890 and I realized I do not have another 2 PCI-Express cables with my PSU. With the 4890 came an adapter that allows you to use the 4pin connectors. Looks like this:



My question is, are you supposed to hook up BOTH the 4pin connections? So I will be using 4 4pin connections total? Also, is it even OK to be using these adapters?

Thanks!

EDIT: Well I went ahead and used all 4 pins and it's working. Another question though, is there anything special I need to do for crossfire? Like in the BIOS? Should they be running at 16x? My motherboard is an Asus M4A78T-E and I think it allows 16x. But in Everest it is reporting this "Bus Type PCI Express 2.0 x16 @ x8"

Catalyst AI has to be on, or "advanced" or something, I think.

For some reason 3Dmark keeps crashing, I think its my overclocking and I just turned it down a bit. How can I check if my PSU is giving the machine enough power? Where do I go in Everest to double check that?