your vcore is not high enough for 4.5ghz.
your qpi is too high for 180bclk.
I heard from a few places that altering PCIE voltage can damage your video cards and usually doesn't improve stability.
You will want to try all CPU PLL settings... Every chip is different.
You also want to specify UCLK, QPI freq, and DRAM freq manually.
For 3x cards you want the ezplug connected because you can exceed the board's max power and burn the ATX24pin.