I am currently trying to overclock my Gigabyte Z68XP-UD3P with a 2600k processor...
The way the BIOS is set up though you have two choices for overclocking:
1) FIXED vcore with the choice of using LLC or not (This will NOT lower vcore at idle)
2) DVID (Dynamic Vcore) but no LLC option (greyed out) so you get vdroop (This WILL lower vcore at idle though)
I am trying to get 4.5Ghz stable, so far i think i can do it with the following settings:
1) FIXED - 1.280v (in BIOS) with LLC6, gives 1.33v under load in windows and 1.32v on Ilde (so vcore remains fixed at all times).
2) DVID - "Normal" with +0.60 gives 1.38v (in BIOS) and gives 1.33-1.37v under load in windows (depending on if its a game or running PRIME etc) BUT drops to 1.00v on Idle.
So my question is, which is better for long term 24/7 use, because i can use DVID and have it lower at idle, but sometimes in games etc it does peak to 1.37v.. OR i use a fixed vcore or 1.33v which also seems stable but this will be at this vcore 24/7 as it is fixed..
I have a Corsair H100 cooler so temps are a non issue at this clock speed.
The great thing overclocking any of the Sandy Bridge K series of CPUs is they are so versatile, no overclock path is set in stone, I wrote the guide below and it is for overclocking all 4 cores with no throttling, which means when you use it you will be running all 4 cores at 4500mhz all the time.
You can always try it for yourself, if you like the end results use it, if not use a different overclock solution, you have good cooling so that is not a problem to run the 4500mhz range.