Thanks guys i've just got back on the task this afternoon.
So i've disabled speedstep and all c states and changed the cpu performance settings in windows to 100% and I can see it's now idling happily at the overclock.
First off I tried for x46 just by kicking up the vcore to 1.22 which made it around 1.25 after LLC. It BSOD 2 minutes and I remembered I left my memory running 2133 so I popped that down to 1600 and ran another test. It got to the 16 minute mark and failed during the 'idle' period.
Do you think this is likely down to the LLC not kicking in fast enough to pull it out of the idle period? In other words should I increase the 'static' vcore and lower the LLC setting or could this be down to something else.
I went ahead and lowered the LLC down to [medium [25%] and kept increasing the vcore until it was stable at x46 which took 1.265v in the BIOS and it basically ran at 1.272v with far less spikes than before, 1.260v was very close to being stable but it froze up. If I turned LLC off completely the drop in vcore under load was very noticeable.
It took too much vcore to get x47 to boot, with the motherboard set to 1.320v I did get into OCCT but it quickly got past 80c so I think my thermal limit lies at x46 assuming I needed that vcore.
I guess i'll have to run some longer tests to check everything is completely stable at these 4.6 settings and see if 2133mhz is stable. If I find increasing the memory clock makes it unstable is their another voltage I should increase?