Hello, I have the same board and I do have the 9590 and yes the FCb BIOS is a mess
, but I do have mine working. What we will be doing here will require you to reinstall windows so I recommend doing a system image backup.
First, clear the CMOS using the jumper on the motherboard. (hold a screw driver there, turn it on for a bit, then shut it off)
After that is complete, just use the BIOS defaults.
Then Flash the bios using a USB flashdrive and use Q-Flash on post. (sidenote: you need to get the amd AHCI preinstall drivers from gigabyte to get the most performance of your hard drive or ssd, stick those on the usb as well)
After it is all loaded go to the bios settings and verify your ram speeds and all that custom stuff you want.
Then reinstall windows using the system image and load that ahci driver I was talking about.
Then you are done. (Oh, and if you plan on running Arma 2 or 3, the engine seems to like the -cpuCount=16 option
)