Overclocking Haswell- small voltage jump(s)

[Chickensoup23]

Hi guys, I've been trying my hand at overclocking my 4670k. I just passed 8 hours of AIDA stress and 4 hours of realbench @ 4.8GHz/1.240 core and it's stable. I've been wanting to try my hand at 5 GHz but here's my problem (and where my lack of experience/knowledge kicks in) - to reach 5 GHz, I need to push my voltage to ~1.280-1.295, or around there, to keep it rock solid.

When I stress, including non-synthetics, while my voltage in AIDA's CPUID is exactly (or very close to) what I put it in the bios, the core voltage in CPU-Z jumps around ~0.015v. While in theory this amount isn't a big deal, it's enough to push my voltage over 1.3v which I'm not very comfortable with. When I tried stressing, CPU-Z indicated 1.310v and I'd personally like to keep it under that for 24/7 use. Also, before any of you guys ask for it, yes, I am in voltage MANUAL MODE. If I'm correct, as it isn't adaptive, manual should not be jumping around whatsoever like this.

Now my question(s);

-Is CPU-Z reading my core voltage correctly? Does my voltage really jump up sometimes by around by ~0.015v?
-If there's nothing about it, given I use Cstates (including 6/7) as well as Speedstep, should 1.315ish keep my CPU safe for 24/7 use?
-How do I correct that?

Also, my i5 is delidded/lapped and I'm on custom cooling. Thanks,
Chicken

[Deleted]

AVX instructions can boost CPU voltage up to 0.1V.

[Chickensoup23]

AVX instructions can boost CPU voltage up to 0.1V.

Any way to prevent that from happening? If not, is my voltage going to ~1.315-1.320 safe for everyday use?

[Deleted]

Consider yourself lucky, i am on 1.3 for 4.4ghz. Since you are on water and have 0 heat problems during stress i dont see a reason to worry at those volts. From the other hand, do you really need 4.8 for everyday use? I mean even wow for me atm when raiding is like 70-75% usage at 4.4. I can't see the reason to go above 4.5ghz unless for the sake to see what your chip can do or bragging rights...so not everyday stuff.

edit: btw dunno what mobo you have but if you find good stable voltage you can do adaptive while keeping the max voltage setting. So when at 800-3.5k run will lower voltage and when say at 4.8@ 1.3.

[Chickensoup23]

Well I'd just like to see what it's capable of, I'm going to be posting in the Mmo-Champ OC'ing leaderboard soon! As far as every day use goes, I'll most likely stick with 4.8ish.

Also, when people adjust voltage, do they take into account the ~0.015v increase under load? (ex: You need 1.250v to attain stability, so in BIOS you put 1.235v). I've heard of higher voltage boosts for adaptive and offset modes while stressing synthetics, but not such a small one.

[Lathais]

How far you can go is highly dependent on your chip. It sounds like going that high is causing some slight stability issues. I would not push it any further as it sounds like that particular chip may not handle it. It sounds like you already got an above average chip, you should be happy you got it where it is.

[Fascinate]

Asus OC software limits voltage to 1.3 on haswell i think thats a good idea. Haswell isnt like sandy where you can push volts to it and have a linear experience, once you go past a certain voltage on haswell the temps skyrocket, you need to find the number before that happens (1.3 is a safe assumption, some can do more but none can do 1.4 without passing this threshold).

[Bizjack]

Do you have your APM on or off? What is your LLC set at?

[chronia]

Any way to prevent that from happening? If not, is my voltage going to ~1.315-1.320 safe for everyday use?

On my MSI board manual voltage is not boosted by AVX instruction use, as soon as i put it on adaptive or offset mode is it though.
But AVX is not the only thing that can boost voltages under load, your LLC settings can also have the voltage fluctuating depending on load, so i would check those if i were you.