I wish I had liquid cooling and a 580 to help out more, the most I have is a 6950 with a 6970 bios
But I doubt its a power draw problem; vid cards dont draw too much power at boot. Also you've said that it'll run at 4.8GHz if you use the optimized cpu oc setting which hints its more likely a UEFI setting problem, but cant be for sure since you've not shown us your settings etc.
Try having a look at this, its for ASUS P67 boards and a bit old but it is a good guide that can be used as reference for any board. I'm sure there's a good guide/sample setting for ASRock boards somewhere in the P67 Extreme4 thread, just too lazy to look through 65 pages.
My wild guess is that you'll have to enable Internal PLL overvoltage, set Turboboost and core power limit to 300, Vcore to fixed at around 1.4-1.45v, adjust load-line calibration to 1 or 2 along with the usual disabling of spread spectrum and so on. That or you just have a faulty board.
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