Ok got my 1st 5Ghz @ 1.63v Vantage completed.
I had to drop the 580's to 880/2200 @ 1.077v to keep under 100c as the high clock speed of the 990x was working them harder.
Now im 5Ghz stable I'll do some COD testing!
enjoy!
PS... I found the limit of the new power supply...
CPU 5.22Ghz 1.66v
with 920/2250 on the GPU's. PSU did an overload shutdown as temps were still fine! (well yes the CPU was a tad hot but not at tMax)
Looks like I might need me a 2nd 1500W PSU to split the load when I overclock the GPUs under water.