VCCIO+VCCSA on Ivy Bridge

[taq8ojh]

I can't seem to find definite answers no matter how hard I google.

Can anyone tell which of these voltages feeds what on IB with certainity?
(and possibly which has higher impact on temperatures)

 

[Goros]

VCCIO is the Memory Controller Voltage and helps stabilize when overclocking RAM or when overclocking multiple components (CPU, GPU, BLCK etc)

VCCSA is System Agent Voltage, and stabilizes or helps overclock BLCK.

VCCIO and VCCSA share some paths in the CPU and need to be raised in tandem and shouldn't be more than a few notches apart for best stability.

Intel max voltage on VCCIO is 1.08v and VCCSA is .971v. Most guides don't recommend exceeding 1.1v for either of those for 24/7 use, and MAX is 1.2v for each. There are some voltage fluctuations so make sure you pad your numbers to keep from breaking max.

I run mine at: VCCSA (1.050), VCCIO (1.08125) for actual voltages in the BIOS of 1.09325 and 1.09125 (with some fluctuations) on both. I have been running them at this 24/7 since May of 2012. I just make sure that the fluctuations never exceed 1.1 and call it good.

Gigabyte boards are reported to be even more picky with VCCSA and VCCIO volts being close together for stability.

There is no reported temp increase or decrease from adding or removing volts to these.

CPU PLL safe range on air is 1.5 to 1.8v and you can shed about 1c for each .1v you cut. I couldn't get stable below 1.65, some people report stable at 1.5!

 

[taq8ojh]

Hmm. I read about that "being within specific range of each other" thing before, but default for VCCSA is 0.925V and VCCIO is 1.050V, which seems like fairly long range to me. If the former affects memory stability and is expected to be raised even a tiny bit, I would have to raise the latter without any specific reason, no? Doesn't sound like a good idea to me, even if these voltages don't affect temperatures much.

I originally foundthis guide, but it looks pretty messy with references to SB and other stuff, so I was more confused than enlightened.

 

[Goros]

It is a long range but those are your "last resort" tweaks once you have found a voltage on your CPU that works but maybe one or two workers fail in prime95, you start adjusting those. With any overclock, you will probably need to pad them just a little but.

That guide hurts my head.

In every IB OC guide I was able to find, you need to adjust your VCCSA and VCCIO for that final bit of stability - in addition, my own personal experience tries that out and shows it true, but most people don't BLCK overclock like I do. I have simultaneous BLCK, CPU, GPU and Memory OC's and so stability without WHEA errors is a tough nut to crack in a system like mine.

For you, I'd just lock the memory in at 1600, bump my mult to x42, get it to around 1.2-1.22v under load etc. It probably means you will have to raise your offset a little more than the .060, but every motherboard is different when it comes to sending power to the cpu.

 

[taq8ojh]

Yea the guide is super confusing.
I also foundthis one, which looks much better, but I just wasn't sure how correct the first one was, so I asked to be sure.

 

[Goros]

Best ones I found were at over at overclock.net