The last motherboard I bought didn't run 5 volt pci cards. it is a MSI K9A2 and only runs 3.3 volts. I looked the GA-990XA-UD3 's manual over and couldn't find it's standard listed (universal, version 2.3 or anything)
(i just clipped this info) The original PCI standard required that plug-in boards use 5V power. As the PCI standard evolved, the option was added for a 3.3V power source. Now, with the latest PCI 2.3 release the 3.3V power supply is required and the 5V power supply is obsolete. (end clip)
I was able to find some Motherboards a few years ago that would accept my MOTU 5volt sound card but not sure how easy that will be today. I had to give the MSI board to my son because I couldn't record with it. If anyone has a new MB thought that runs 5 volts and SATA 3 let me know! TIA