don;t have one of these but as i recall one side says it's for dual sided ssd's and that side is the primary one used if doing raid 1/0 also ONLY ONE SLOT CAN BE USED IF BOOTING FROM THE CARD, the other 3 can be used as a non booting array
Slots 4/5/3 are the only HP recommended slots
so you can not do a bootable raid on this card
if using 2 ssd's a x8 slot is required, 4 ssd's must use a x16 slot
you must be running a later bios the latest release is highly recommended
you can boot from the card using only one ssd slot as the boot device with the other 3 as non bootable single drives or as a single raid using the 3 remaining ssd'd