I managed to get 4.5GHz stable on Vcore 1.35 by reducing PLL to 1.65! I never knew PLL could improve stability so much, but it seems as though it's helping a lot of people stable their higher overclocks!
I ran P95 27.7 AVX blend for 13 hours and it was rock solid on a much lower Vcore! Screenshot:
My idle voltage is 1.368, V under load is 1.352! YAY
I'm very happy about this, will try 4.7 soon with Vcore set to 1.38 in CPU-Z and we'll see how it goes :)